2041.pdf
[0.36 MB]
Link will provide options to open or save document.

File Format:

Adobe Reader

ENVIRONMENTAL ASSESSMENT
DESIGNATION OF CRITICAL HABITAT
FOR THE
MEXICAN SPOTTED OWL
(Strix occidentalis lucida)
Prepared by
U.S. Fish and Wildlife Service
New Mexico Ecological Services Field Office
Albuquerque, New Mexico
TABLE OF CONTENTS
1.0 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Need for the Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Critical Habitat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.0 Description of Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 No Action Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Action Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.1 Designation Identified in the Final Rule (Proposed Action) . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.2 Designation Identical to the 1995 Final Rule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.3 Designation of the Entire Historical Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.4 Designation of Only the Occupied Portions of Historical Range . . . . . . . . . . . . . . . . . . 10
3.0 Description of the Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1 Physical and Biological Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2 Human Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.3 Tribal Lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.0 Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.1 Effects on Mexican Spotted Owl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.2 Effect on Fish, Wildlife and Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.3 Recreational Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.4 Agricultural, Including Timber, Fuelwood, and Grazing Impacts . . . . . . . . . . . . . . . . . . 17
4.5 Socioeconomic Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.6 Direct and Indirect Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.7 Cumulative Impact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.0 Council on Environmental Quality Analysis of Significance . . . . . . . . . . . . . . . . . . . . . . . . 20
References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
ENVIRONMENTAL ASSESSMENT
DESIGNATION OF CRITICAL HABITAT FOR MEXICAN SPOTTED OWL
1.0 Purpose
The purpose of designating critical habitat for the threatened Mexican spotted owl (Strix
occidentalis lucida) is to utilize provisions of the Endangered Species Act of 1973, as amended
(Act), to help achieve the species’ conservation. The purpose of the Act is to conserve the
ecosystems upon which endangered and threatened species depend. Critical habitat designation
identifies those areas that are essential to the survival and recovery of the Mexican spotted owl,
and describes those physical and biological features within those areas that require special
management considerations to achieve conservation of the species.
1.1 Need for the Action
The need for this action is to comply with section 4 of the Act, which requires that critical habitat
be designated for endangered and threatened species unless such designation is not prudent. In
the final rule listing the Mexican spotted owl as a threatened (58 FR 14248), we, the Fish and
Wildlife Service, found that although considerable knowledge of owl habitat needs had been
gathered in recent years, habitat maps in sufficient detail to accurately delineate critical habitat
areas were not available. After the listing, we began gathering the data necessary to develop a
proposed rule to designate critical habitat. A final rule designating critical habitat for the
Mexican spotted owl was published on June 6, 1995 (60 FR 29914). In 1996, the Tenth Circuit
Court of Appeals in Catron County Board of Commissioners v. United States Fish and Wildlife
Service, 75 F.3d 1429, 1439 (10th Cir. 1996), ruled that the Service had to comply with the
National Environmental Policy Act (NEPA) before designating critical habitat for two desert
fish, the spikedace and loach minnow. In addition, a federal district court in New Mexico later
set aside the final rule designating critical habitat for the owl and forbid the Service from
enforcing critical habitat for the owl (Coalition of Arizona-New Mexico Counties for Stable
Economic Growth v. U.S. Fish and Wildlife Service, No. 95-1285-M Civil, April 1, 1997). As a
result of these court rulings, we removed the critical habitat designation for the owl from the
Code of Federal Regulations on March 25, 1998 (63 FR 14378).
On March 13, 2000, the United States District Court for the District of New Mexico, (Southwest
Center for Biological Diversity and Silver v. Babbitt and Clark, CIV 99-519 LFG/LCS-ACE),
ordered us to propose critical habitat within 4 months of the court order, and to complete and
publish a final designation of critical habitat for the Mexican spotted owl by January 15, 2001.
On July 21, 2000, we published a proposal to designate critical habitat for the Mexican spotted
owl in Arizona, Colorado, New Mexico, and Utah, mostly on Federal lands (65 FR 45336). This
final rule is in response to that court order. Critical habitat is one of several provisions of the
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
2
ESA that aid in protecting the habitat of listed species until populations have recovered and
threats have been minimized so that the species can be removed from the list of threatened and
endangered species. Critical habitat designation is intended to assist in achieving long-term
protection and recovery of Mexican spotted owls and the ecosystems upon which they depend,
by subjecting areas designated as critical habitat to section 7(a)(2) of the Act, thereby requiring
consultation for Federal actions that may affect these areas in order to avoid destruction or
adverse modification of this habitat. Further explanation of critical habitat and its
implementation is provided below.
1.2 Background
The Mexican spotted owl (Strix occidentalis lucida) is one of three subspecies of spotted owl
occurring in the United States; the other two are the northern spotted owl (S. o. caurina) and the
California spotted owl (S. o. occidentalis). The Mexican spotted owl is distinguished from the
California and northern subspecies chiefly by geographic distribution and plumage. The
Mexican spotted owl is mottled in appearance with irregular white and brown spots on its
abdomen, back, and head. The spots of the Mexican spotted owl are larger and more numerous
than in the other two subspecies, giving it a lighter appearance.
The Mexican spotted owl has the largest geographic range of the three subspecies. The range
extends north from Aguascalientes, Mexico, through the mountains of Arizona, New Mexico,
and western Texas, to the canyons of Utah and Colorado, and the Front Range of central
Colorado. Much remains unknown about the species' distribution in Mexico, where much of the
owl's range has not been surveyed. The owl occupies a fragmented distribution throughout its
United States range, corresponding to the availability of forested mountains and canyons, and in
some cases, rocky canyonlands. Although there are no estimates of the owl’s historical
population size, its historical range and present distribution are thought to be similar.
According to the Recovery Plan for the Mexican Spotted Owl (United States Department of
Interior 1995) (Recovery Plan), 91 percent of owls known to exist in the United States between
1990 and 1993 occurred on land administered by the U.S. Forest Service (FS); therefore, the
primary administrator of lands supporting owls in the United States is the FS. These numbers are
based upon preliminary surveys that were focused on National Forests in the southwest.
Nevertheless, most owls have been found within Region 3 of the FS, which includes 11 National
Forests in New Mexico and Arizona. FS Regions 2 and 4, including two National Forests in
Colorado and three in Utah, support fewer owls. The range of the owl is divided into 11
Recovery Units (RU), 5 in Mexico and 6 in the United States, as identified in the Recovery Plan.
The Recovery Plan also identifies recovery criteria and provides distribution, abundance, and
density estimates by RU. Of the RUs in the United States, the Upper Gila Mountains RU,
located in the central portion of the species’ U.S. range in central Arizona and west-central New
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
3
Mexico, contains over half of known owl sites. Owls here use a wide variety of habitat types,
but are most commonly found inhabiting mature mixed-conifer and ponderosa pine-Gambel oak
forests. The Basin and Range-East RU encompasses central and southern New Mexico, and
includes numerous parallel mountain ranges separated by alluvial valleys and broad, flat basins.
Most breeding spotted owls occur in mature mixed-conifer forest. The Basin and Range-West
RU contains mountain ranges separated by non-forested habitat. These “sky island” mountains
of southern Arizona and far-western New Mexico contain mid-elevation mixed-conifer forest and
lower elevation Madrean pine-oak woodlands that support spotted owls. The Colorado Plateau
RU includes northern Arizona, southern Utah, southwestern Colorado, and northwestern New
Mexico, with owls generally confined to deeply incised canyon systems and wooded areas of
isolated mountain ranges. The Southern Rocky Mountains-New Mexico RU consists of the
mountain ranges of northern New Mexico. Owls in this unit typically inhabit mature mixed-conifer
forest in steep canyons. The smallest number of spotted owls occurs in the Southern
Rocky Mountains-Colorado RU. This unit includes the southern Rocky Mountains in Colorado,
where spotted owls are largely confined to steep canyons, generally with significant rock faces
and various amounts of mature coniferous forest. The critical habitat units identified in this
designation are all within these RUs.
A reliable estimate of the numbers of owls throughout its entire range is not currently available.
Using information gathered by Region 3 of the FS, Fletcher (1990) calculated that 2,074 owls
existed in Arizona and New Mexico in 1990. Based on more up-to-date information, we
subsequently modified Fletcher’s calculations and estimated a total of 2,160 owls throughout the
United States (USDI 1991). However, these numbers are not considered reliable estimates of
current population size for a variety of statistical reasons, and a pilot study (Ganey et al. 1999)
conducted in 1999 estimated the number of owls for the upper Gila Mountains Recovery Unit
(exclusive of tribal lands) as 2,950 (95 percent confidence interval 717-5,183).
Mexican spotted owls nest, roost, forage, and disperse in a diverse array of biotic communities.
Nesting habitat is typically in areas with complex forest structure or rocky canyons, and contains
uneven-aged, multi-storied mature or old-growth stands that have high canopy closure (Ganey
and Balda 1989, USDI 1991). In the northern portion of the range (Utah and Colorado), most
nests are in caves or on cliff ledges in steep-walled canyons. Elsewhere, the majority of nests
appear to be in Douglas fir (Pseudotsuga menziesii) trees (Fletcher and Hollis 1994, Seamans
and Gutierrez 1995). A wide variety of tree species is used for roosting; however, Douglas fir is
the most commonly used species in mixed conifer forests (Ganey 1988, Fletcher and Hollis
1994, Young et al. 1998). Owls generally use a wider variety of forest conditions for foraging
than they use for nesting/roosting.
Seasonal movement patterns of Mexican spotted owls are variable. Some individuals are year-round
residents within an area, some remain in the same general area but show shifts in habitat
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
4
use patterns, and some migrate considerable distances (20-50 kilometers (km)) (12-31 miles
(mi)) during the winter, generally migrating to more open habitat at lower elevations (Ganey and
Balda 1989b, Willey 1993, Ganey et al.1998). The home-range size of Mexican spotted owls
appears to vary considerably among habitats and/or geographic areas (USDI 1995), ranging in
size from 261-1,487 ha (647-3,688 ac) for individuals birds, and 381-1,551 ha (945-3,846 ac) for
pairs (Ganey and Balda 1989b, Ganey et al. 1999). Little is known about habitat use by juveniles
dispersing soon after fledging. Ganey et al. (1998) found dispersing juveniles in a variety of
habitats ranging from high-elevation forests to piñon-juniper woodlands and riparian areas
surrounded by desert grasslands.
Mexican spotted owls do not nest every year. The owl’s reproductive pattern varies somewhat
across its range. In Arizona, courtship usually begins in March with pairs roosting together
during the day and calling to each other at dusk (Ganey 1988). Eggs are typically laid in late
March or early April. Incubation begins shortly after the first egg is laid, and is performed
entirely by the female (Ganey 1988). The incubation period is about 30 days (Ganey 1988).
During incubation and the first half of the brooding period, the female leaves the nest only to
defecate, regurgitate pellets, or receive prey from the male, who does all or most of the hunting
(Forsman et al. 1984, Ganey 1988). Eggs usually hatch in early May, with nestling owls
fledging 4 to 5 weeks later, and then dispersing in mid-September to early October (Ganey
1988).
Little is known about the reproductive output for the spotted owl. It varies both spatially and
temporally (White et al. 1995), but the subspecies demonstrates an average annual rate of about
one young per pair. Based on short-term population and radio tracking studies, and longer-term
monitoring studies, the probability of an adult owl surviving from 1 year to the next is 80 to 90
percent. Average annual juvenile survival is considerably lower, at 6 to 29 percent, although it is
believed these estimates may be artificially low due to the high likelihood of permanent dispersal
from the study area, and the lag of several years before marked juveniles reappear as territory
holders and are detected as survivors through recapture efforts (White et al. 1995). Little
research has been conducted on the causes of mortality, but predation by great horned owls
(Bubo virginianus), northern goshawks (Accipter gentilis), red-tailed hawks (Buteo jamaicensis),
and golden eagles (Aquila chrysaetos), as well as starvation, and collisions (e.g., with cars,
powerlines), may all be contributing factors.
Mexican spotted owls consume a variety of prey throughout their range, but commonly eat
small- and medium-sized rodents such as woodrats (Neotoma spp.), peromyscid mice
(Peromyscus spp.), and microtine voles (Microtus spp.). Owls also may consume bats, birds,
reptiles, and arthropods (Ward and Block 1995). Each prey species uses a unique habitat, so that
the differences in the owl’s diet across its range likely reflect geographic variation in population
densities and habitats of both the prey and the owl (Ward and Block 1995). Deer mice (P.
maniculatus) are widespread in distribution in comparison to brush mice (P. boylei), which are
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
5
restricted to drier, rockier substrates, with sparse tree cover. Mexican woodrats (N. mexicana)
are typically found in areas with considerable shrub or understory tree cover and high log
volumes or rocky outcrops. Mexican voles (M. mexicanus) are associated with high herbaceous
cover, primarily grasses, whereas long-tailed voles (M. longicaudus) are found in dense
herbaceous cover, primarily forbs, with many shrubs and limited tree cover.
Two primary reasons were cited for listing the owl as threatened in 1993: (1) historical alteration
of its habitat as the result of timber management practices, specifically the use of even-aged
silviculture, and the threat of these practices continuing; and (2) the danger of catastrophic
wildfire. The Recovery Plan for the owl outlines management actions that land management
agencies and Indian tribes should undertake to remove recognized threats and recover the spotted
owl. This critical habitat designation is based on recovery needs and guidelines identified in the
Recovery Plan.
1.3 Critical Habitat
Critical habitat is defined in section 3(5)(A) of the Act as – (i) the specific areas within the
geographical area occupied by a species, at the time it is listed in accordance with the Act, on
which are found those physical or biological features (I) essential to the conservation of the
species and (II) that may require special management considerations or protection; and (ii)
specific areas outside the geographical area occupied by a species at the time it is listed, upon a
determination that such areas are essential for the conservation of the species. The term
"conservation," as defined in section 3(3) of the Act, means "the use of all methods and
procedures which are necessary to bring an endangered species or threatened species to the point
at which the measures provided pursuant to this Act are no longer necessary" (i.e., the species is
recovered and removed from the list of endangered and threatened species).
Section 4(b)(2) of the Act requires that we base critical habitat designation on the best scientific
and commercial data available, taking into consideration the economic impact, and any other
relevant impact, of specifying any particular area as critical habitat. We may exclude areas from
critical habitat designation if we determine that the benefits of exclusion outweigh the benefits of
including the areas as critical habitat, provided the exclusion will not result in the extinction of
the species. We are also required to consider those habitat features (primary constituent
elements) that provide for the physiological, behavioral, and ecological requirements essential
for the conservation of the species and that may require special management considerations or
protection. Such physical and biological features, as outlined in 50 CFR 424.12, include, but are
not limited to, the following:
(1) Space for individual and population growth, and for normal behavior;
(2) Food, water, or other nutritional or physiological requirements;
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
6
(3) Cover or shelter;
(4) Sites for breeding, reproduction, or rearing of offspring; and
(5) Habitats that are protected from disturbances or are representative of the historic
geographical and ecological distribution of a species.
2.0 Description of Alternatives
The Service considered the No Action Alternative as required by NEPA. The Action Alternative
is to designate critical habitat as ordered by the court.
2.1 No Action Alternative
The No Action alternative is defined as a decision to forgo the designation of critical habitat for
the Mexican spotted owl. This alternative serves to delineate the existing environment and
conditions that are anticipated to result from the listing of the species, without designation of
critical habitat. Since the listing of the species as threatened, the Mexican spotted owl has been
protected under section 7 of the Act by prohibiting Federal agencies from implementing actions
that would jeopardize the continued existence of the species. This protection under the Act is
considered the baseline against which we evaluate the action alternatives described below.
2.2 Action Alternatives
The Action Alternatives each would include designation of critical habitat in areas believed to
contain the physical and biological features upon which the Mexican spotted owl depends. The
Act refers to these essential habitat features as “primary constituent elements.” We determined
the primary constituent elements for Mexican spotted owl from studies of their habitat
requirements and the information provided in the Recovery Plan (USDI 1995 and references
therein). Since owl habitat can include both canyon and forested areas, we identified primary
constituent elements in both areas. Within restricted habitat (described in the Recovery Plan,
Volume I, part III, pages 84-95, including Table III.B.1), mixed conifer, pine-oak, and riparian
forest types that currently contain or may attain the habitat attributes believed capable of
supporting nesting and roosting owls include:
- high basal area of large diameter trees;
- moderate to high canopy closure;
- wide range of tree sizes suggestive of uneven-age stands;
- multi-layered canopy with large overstory trees of various species;
- high snag basal area;
- high volumes of fallen trees and other woody debris;
- high plant species richness, including hardwoods; and
- adequate levels of residual plant cover to maintain fruits, seeds, and regeneration to
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
7
provide for the needs of Mexican spotted owl prey species.
For canyon habitat, the primary constituent elements include the following attributes:
- cooler and often more humid conditions than the surrounding area;
- clumps or stringers of trees and/or canyon wall containing crevices, ledges, or caves;
- high percent of ground litter and woody debris; and
- riparian or woody vegetation (although not at all sites).
The forest habitat attributes listed above usually develop with increasing forest age, but their
occurrence may vary by location, past forest management practices or natural disturbance events,
forest type, and productivity. These characteristics may also develop in younger stands,
especially when the stands contain remnant large trees or patches of large trees from earlier
stands. Certain forest management practices may also enhance tree growth and mature stand
characteristics where the older, larger trees are allowed to persist.
Canyon habitats used for nesting and roosting are typically characterized by cooler conditions
found in steep, narrow canyons, often containing crevices, ledges, and/or caves. These canyons
frequently contain small clumps or stringers of ponderosa pine, Douglas fir, white fir, and/or
piñon-juniper. Deciduous riparian and upland tree species may also be present. Adjacent
uplands are usually vegetated by a variety of plant associations including piñon-juniper
woodland, desert scrub vegetation, ponderosa pine-Gambel oak, ponderosa pine, or mixed
conifer. Owl habitat may also exhibit a combination of attributes between the forested and
canyon types.
2.2.1 Designation as identified in the Final Rule
Our preferred alternative is to finalize the designation of critical habitat as described in the final
rule signed on January 16, 2001, and becoming effective 30 days following publication in the
Federal Register. In developing this alternative, we reviewed the overall approach to the
conservation of the species since the species’ listing in 1993 (58 FR 14248); examined the
critical habitat units identified in the previous proposed (59 FR 63162) and final critical habitat
rules (60 FR 29914); considered new location data and habitat requirements for recovery and
definitions described in the Recovery Plan (USDI 1995), and information received during the
comment periods for the proposed rule (65 FR 45336; 65 FR 63047). All protected and
restricted habitat as described in the Recovery Plan is designated as critical habitat. The critical
habitat designation does not include tribal lands; FS lands within Arizona and New Mexico; Fort
Carson, Colorado; and low-density areas. However, the critical habitat designation does include
FS lands in Utah and Colorado, and other Federal lands in Arizona, New Mexico, Colorado, and
Utah, used by currently known populations of Mexican spotted owls. In addition, we included
areas where owls could occur based on the presence of the appropriate topography, elevation, and
habitat types (protected and restricted habitat areas as defined in the Recovery Plan).
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
8
All areas designated as critical habitat for the Mexican spotted owl are within the geographical
area occupied or potentially occupied by the Mexican spotted owl, in accordance with section
3(5)(A)(i) of the Act, which provides that areas outside the geographical area occupied by the
species may meet the definition of critical habitat upon determination that they are essential for
the conservation of the species. It is essential to protect all designated occupied areas as well as
potentially occupied areas that will provide habitat for recovery of this species.
The designated critical habitat constitutes our best assessment of areas needed for the
conservation of the owl and is based on the best scientific and commercial information available.
The areas are essential to the conservation of the species because they either currently support
populations of the owl, or because they currently possess the necessary habitat requirements for
nesting, roosting, and foraging (see description of primary constituent elements). Existing
human-constructed features and structures within designated critical habitat (e.g., buildings,
roads, etc.) do not contain Mexican spotted owl habitat and are not considered critical habitat.
Some units that were proposed as critical habitat were significantly reduced within Arizona and
New Mexico because of the exclusion of FS lands. Nevertheless, the remaining Federal lands
(e.g., Bureau of Land Management (BLM), National Park Service, etc.) within the mapped
boundaries in Arizona and New Mexico, are designated as critical habitat. The critical habitat
designation on Federal lands adjacent to FS lands within Arizona and New Mexico will ensure
that “special management considerations or protections” are provided for the Mexican spotted
owl on all Federal lands, pursuant to the definition of critical habitat in section 3 of the Act. We
did not designate some areas that are known to have widely scattered owl sites, low population
densities, and/or marginal habitat quality, which are not considered to be essential to this species’
survival or recovery.
State and private lands are not included in this designation. The overwhelming majority of
Mexican spotted owl records are from Federal and tribal lands, indicating that those lands are
essential to the species’ recovery. However, we did not include tribal lands or National Forest
lands within Arizona and New Mexico in the designation because we determined that the
management of the Mexican spotted owl on those lands with appropriate habitat management
plans provides substantial protection and that designation of critical habitat would provide little
or no additional benefit to the species.
2.2.2 Designation identical to the 1995 Final Rule
The 1995 final rule designating critical habitat for the Mexican spotted owl was based on the
proposed critical habitat designation published in 1994 (59 FR 63162). The previous critical
habitat designation was based on extensive use and evaluation of owl habitat and territory maps,
vegetation maps, aerial photography, and field verification to identify areas for designation as
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
9
critical habitat. Several qualitative criteria (including currently suitable habitat, large contiguous
blocks of habitat, occupied habitat, range wide distribution, the need for special management or
protection, adequacy of existing regulatory mechanisms) were considered when identifying
critical habitat areas. The 1995 critical habitat designation was published prior to the completion
of the Recovery Plan for the Mexican spotted owl and was based on information that was current
at that time. As a result of several court rulings, as discussed in section 1.1 of this document, we
removed the critical habitat designation for the owl from the Code of Federal Regulations on
March 25, 1998 (63 FR 14378).
Five years have passed since the 1995 critical habitat designation and there have been substantial
changes in the information available. Therefore, a designation of critical habitat that included
only those areas proposed in 1994 and finalized in 1995, would not conform to the requirement
of the Endangered Species Act to consider the best available scientific and commercial
information in designation of critical habitat. In addition, there have been substantial changes in
policy and court interpretations of critical habitat that require consideration of areas not included
in the 1995 designation. For the above reasons, this alternative was not considered to be viable
and will not be analyzed further.
2.2.3 Designation of the Entire Historical Range
We considered proposing to designate the entire historical range of the Mexican spotted owl,
which would include all areas where owls have been known to occur. In addition to the critical
habitat units identified in the proposed rule (65 FR 45336), areas such Dinosaur National Park in
northwest Colorado; Mesa Verde National Park, Ute Mountain Ute Reservation, Southern Ute
Reservation, other Forest Service and Bureau of Land Management land in southwest Colorado;
and the Guadalupe and Davis Mountains in southwest Texas would be included, as well as State
and private lands within the critical habitat boundaries. All areas that are known to have widely
scattered owl sites, low population densities, and/or marginal habitat quality, which are not
considered to be essential to this species' survival or recovery, would be included in this
alternative. Given that the majority of the owl’s range occurs on Federal and tribal lands, State
and private lands are not considered essential to the recovery of the species and therefore are not
designated as critical habitat. Exclusion of State, private, and some tribal lands from the
designation will not result in extinction or slow recovery of this species. Additionally, much of
these lands do not meet part (5)(A)(i)(I) of the definition of critical habitat stated above; we are,
therefore, not designating those lands as critical habitat. As a result, this alternative was removed
from further consideration because we concluded that the Proposed Action of designating 1.9
million hectares (ha) (4.6 million acres (ac)) of Federal lands, is sufficient to provide for the
survival and recovery of the species within all major segments of the owls historical range.
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
10
2.2.4 Designation of Only The Occupied Portions of the Historical Range
We considered only including those areas currently known to be occupied. The Service believes
the occupied and potentially occupied areas included in the final designation of critical habitat,
signed on January 16, 2001, and becoming effective 30 days following publication in the Federal
Register, are needed for the conservation of the Mexican spotted owl and that recovery of the
species will require all of these areas. Omission of any critical habitat unit may result in loss of
significant genetic and geographic components of the species, unless those lands provide “special
management considerations or protections” for the Mexican spotted owl, pursuant to the
definition of critical habitat in section 3 of the Act. If “special management considerations or
protections” are not provided and lands are excluded from the designation, the value of critical
habitat in those areas would be undermined in terms of size, connectivity, and habitat and
community diversity. No viable alternative exists if portions of the critical habitat in the
Proposed Action are omitted; thus, this alternative was not considered viable.
3.0 Description of the Affected Environment
The geographic area for the Proposed Action includes the portions of canyon and montane forest
habitats across a range that extends from southern Utah and the front range of Colorado, through
Arizona and New Mexico. We designated approximately 1.9 million hectares (ha) (4.6 million
acres (ac)) of critical habitat in Arizona, Colorado, New Mexico, and Utah, on Federal lands that
are composed of a combination of protected and restricted habitat within forested and canyon
habitat types.
3.1. Physical and Biological Environment
The Mexican spotted owl occupies a broad geographic area, largely restricted to montane forests
and canyons. The owl occurs in disjunct localities, corresponding to isolated mountain ranges
and canyons (USDI 1995). These forested mountain ranges and canyons encompass a wide array
of physical, climatic, and habitat features. The range of the owl is divided into 11 Recovery
Units (RU), 5 in Mexico and 6 in the United States, as identified in the Recovery Plan (USDI
1995). Only those RUs within the United States are included in this designation. The Recovery
Plan identified these RUs based on the following considerations (in order of importance: 1)
physiographic province, 2) biotic regimes, 3) perceived threats, 4) administrative boundaries, and
5) known patterns of owl distribution. The four major physiographic provinces that were used in
delineating the RUs in the United States are the Colorado Plateau, Basin and Range, Southern
Rocky Mountains, and Upper Gila Mountains.
The vegetative communities and structural attributes used by the owl vary across the designated
critical habitat. They are composed primarily of warm-temperate and cold-temperate forests,
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
11
and, to a lesser extent, woodlands and riparian deciduous forests. The mixed-conifer community
appears to be frequently used throughout most portions of the owl’s range (Skaggs and Raitt
1988; Ganey and Balda 1989, 1994; Service 1995). Mixed-conifer forests contain several
species of overstory trees. The most common are white fir (Abies concolor), Douglas fir
(Pseudotsuga menziesii), and ponderosa pine (Pinus ponderosa). Less common species are
southwestern white pine (P. strobiformis), limber pine (P. flexilis), aspen (Populus tremuloides),
and corkbark fir (Abies lasiocarpa var. arizonica). The understory within mixed-conifer
communities provides important roosting sites for Mexican spotted owls. The understory usually
contains the same conifer species found in the overstory, with Gambel oak (Quercus gambelii),
maples (Acer grandidentatum and A. glabrum), and New Mexico locust (Robinia neomexicana)
also present. Montane riparian canyon bottoms used by owls in the mixed-conifer zone may
contain box elder (Acer negundo), narrowleaf cottonwood (Populus angustifolia), maples (Acer
spp.), and alders (Alnus spp.).
Mexican spotted owls nest, roost, forage, and disperse in a diverse array of biotic communities.
Nesting habitat is typically in areas with complex forest structure or rocky canyons, and contains
uneven-aged, multi-storied mature or old-growth stands that have high canopy closure (Ganey
and Balda 1989, USDI 1991). In the northern portion of the range (southern Utah and Colorado),
most nests are in caves or on cliff ledges in steep-walled canyons. Elsewhere, the majority of
nests appear to be in Douglas fir trees (Fletcher and Hollis 1994; Seamans and Gutierrez 1995).
A wider variety of tree species is used for roosting; however Douglas fir is the most commonly
used species (Ganey 1988, Fletcher and Hollis 1994, Young et al 1998). Spotted owls generally
use a wider variety of forest conditions (mixed conifer, pine-oak, ponderosa pine, piñon-juniper)
for foraging than they use for nesting/roosting. Canyon habitats used for nesting and roosting are
typically characterized by the cooler conditions found in steep, narrow canyons, often containing
crevices, ledges, and/or caves. These canyons frequently contain small clumps or stringers of
ponderosa pine, Douglas fir, white fir, and/or pinon-juniper. Deciduous riparian and upland tree
species may also be present. Adjacent uplands are usually vegetated by a variety of plant
associations including pinon-juniper woodland, desert scrub vegetation, ponderosa pine-Gambel
oak, ponderosa pine, or mixed conifer.
Mexican spotted owls consume a variety of prey throughout their range, but commonly eat
small- and medium-sized rodents such as woodrats (Neotoma spp.), peromyscid mice
(Peromyscus spp.), and microtine voles (Microtus spp.). Owls also may consume bats, birds,
reptiles, and arthropods (Ward and Block 1995). Each prey species uses a unique habitat, so that
the differences in the owl’s diet across its range likely reflect geographic variation in population
densities and habitats of both the prey and the owl (Ward and Block 1995). Deer mice (P.
maniculatus) are widespread in distribution in comparison to brush mice (P. boylei), which are
restricted to drier, rockier substrates, with sparse tree cover. Mexican woodrats (N. mexicana)
are typically found in areas with considerable shrub or understory tree cover and high log
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
12
volumes or rocky outcrops. Mexican voles (M. mexicanus) are associated with high herbaceous
cover, primarily grasses, whereas long-tailed voles (M. longicaudus) are found in dense
herbaceous cover, primarily forbs, with many shrubs and limited tree cover.
The Mexican Spotted Owl Recovery Plan provides for three levels of habitat management:
protected areas, restricted areas, and other forest and woodland types. Protected habitat includes
all known owl sites, all areas within mixed conifer or pine-oak types with slopes greater than 40
percent where timber harvest has not occurred in the past 20 years, and all reserved lands
(designated Wilderness or other legally or administratively reserved areas). The Recovery Plan
recommends that protected areas, or Protected Activity Centers (PACs), be designated around
known owl sites. A PAC would include an area of at least 243 ha (600 ac) that includes the best
nesting and roosting habitat in the area. Based on available data, the recommended size for a
PAC includes, on average, 75 percent of the foraging area of an owl.
Restricted habitat includes mixed conifer forest, pine-oak forest, and riparian areas outside of
protected areas described above (i.e., areas that do not currently contain owls). These areas are
essential to the conservation of the species because the Recovery Plan identifies these areas as
providing additional owl habitat for future occupancy. All restricted habitat is designated as
critical habitat and has or is capable of having one or more of the primary constituent elements.
Other forest and woodland types (ponderosa pine, spruce-fir, piñon-juniper, and aspen) are not
expected to provide nesting or roosting habitat for the Mexican spotted owl (except when
associated with rock canyons). Thus, these other forest and woodland types are not considered to
be critical habitat unless specifically delineated within PACs. Although the Recovery Plan does
not provide owl-specific guidelines to managing these areas, these and other habitat types may
provide important foraging and dispersal habitat for the owl, particularly if adjacent to protected
or restricted areas. Therefore, these areas should be managed for landscape diversity, mimicking
natural disturbance patterns, incorporating natural variation in stands, and retaining special
features such as snags and large trees (USDI 1995).
3.2 Human Environment
There is a wide diversity of human activities and land uses throughout or adjacent to the areas
designated as critical habitat in Arizona, Colorado, New Mexico, and Utah. Uses include timber
harvest, personal use commodities (fuelwood, vigas, latillas), livestock grazing, fire management
activities, oil and gas leases, sand and gravel extraction, mining, military maneuvers, road
development, utility corridors, hydroelectric facilities, geothermal development, and a wider
variety of recreational activities.
The designation of critical habitat directly affects only Federal agencies. The Act requires
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
13
Federal agencies to ensure that actions they fund, authorize, or carry out do not destroy or
adversely modify critical habitat to the extent that the action appreciably diminishes the value of
the critical habitat for the survival and recovery of the species. Individuals, organizations, States,
local and Tribal governments, and other non-Federal entities are only affected by the designation
of critical habitat if their actions occur on Federal lands, require a Federal permit, license, or
other authorization, or involve Federal funding.
Although there are many parcels of State and private lands within the critical habitat boundaries,
these lands are not considered critical habitat. Given that the majority of the owl’s range occurs
on Federal and tribal lands, we do not feel that State and private lands are essential to the
recovery of the subspecies and should not be designated as critical habitat.
3.3 Tribal lands
Several tribes are located within the geographical area occupied by the Mexican spotted owl.
Each tribe is a sovereign entity, with its own government and community. There is a unique and
distinctive political relationship between the United States and Native American governments, as
defined by treaties, statutes, court decisions, and the Constitution, that differentiate Native
American governments from other interests and constituencies, and that relationship extends to
all Federal governments.
In our 1994 critical habitat proposal for the owl, we identified lands of the White Mountain
Apache, Jicarilla Apache, Mescalero Apache, San Carlos Apache, Southern Ute, Ute Mountain
Ute, and Navajo Nation Tribes as containing habitat that may be appropriate for designation of
critical habitat. The Proposed Action included lands of the Mescalero Apache, San Carlos
Apache, and Navajo Nation that are currently known to support owls. However, after
reevaluating the available data, we no longer feel that designating these areas is appropriate. As
provided under section 4(b)(2) of the Act, we solicited information on the possible economic and
other impacts of critical habitat designation, and continued to work with the tribes in developing
voluntary measures adequate to conserve Mexican spotted owls on tribal lands. During the
second comment period, the Mescalero Apache and Navajo Nation completed management plans
for the Mexican Spotted Owl. The San Carlos Apache Reservation management plan is
substantially complete and is expected to be completed in March of 2001. We reviewed a draft
of their plan and found it to be consistent with the Recovery Plan. We determined that adequate
special management is being provided for the Mexican spotted owl on the Navajo Nation and
Mescalero Apache lands and, therefore, they were not included in the designation since they do
not meet the definition of critical habitat. In the case of the San Carlos Apache Reservation we
found, in accordance with section 4(b)(2) of the Act, that the benefits of excluding their lands
outweighed the benefits of including them in the designation. We reviewed each of these plans
and determined that the management of the Mexican spotted owl will provide substantial
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
14
protection for the relevant habitat areas, and that designation of critical habitat will provide little
or no additional benefit to the species, particularly since all the areas are presently occupied by
the owl. More importantly, designation of critical habitat would be expected to adversely impact
our working relationship with the tribes and we believe that Federal regulation through critical
habitat designation would be viewed as an unwarranted and unwanted intrusion into tribal natural
resource programs. Our working relationship with the tribes has been extremely beneficial in
implementing natural resource programs of mutual interest.
During our review of the Navajo Nation management plan for the Mexican spotted owl, we
concluded that there is a unique land ownership of Navajo National Monument and Canyon de
Chelly, wherein the land is owned by the Navajo Nation, but under the management authority
and administration of the National Park Service. Although other lands owned by the Navajo
Nation were excluded from critical habitat, critical habitat was designated on Navajo National
Monument and Canyon de Chelly, because the National Park Service retains management
authority over these lands, and any management that may have the potential to adversely affect
the owl or its critical habitat would stem from their actions.
Since our previous critical habitat designation, we learned that the Southern Ute Reservation has
not supported spotted owls historically, and our assessment revealed that the Reservation does
not support habitat essential to the species' conservation. Thus, lands of the Southern Ute
Reservation do not meet part (5)(A)(i)(I) of the definition of critical habitat stated above; we are,
therefore, not designating those lands as critical habitat.
Lands of the Ute Mountain Ute Tribe are not being designated due to the low population density
and isolation from other occupied areas in Colorado, New Mexico, and Utah. The owls on these
lands in southwestern Colorado are not believed to be essential for the survival or recovery of the
species. Thus, these lands do not meet part (5)(A)(i)(I) of the definition of critical habitat stated
above; we are, therefore, not designating those lands as critical habitat.
4.0 Environmental Consequences
This section reviews the expected environmental consequences of designating critical habitat for
the Mexican spotted owl under the proposed action and the environmental consequences of the
No Action Alternative. Regardless of which alternative is chosen, in accordance with section
7(a)(2) of the Act, Federal agencies are required to review actions they authorize, fund, or carry
out to determine the effects of Proposed Actions on federally listed species. If the Federal
agency determines that its action may affect a listed species, it must enter into consultation with
the Fish and Wildlife Service. The consultation results in a biological opinion from the Service
as to whether the Proposed Action is likely to jeopardize the continued existence of the species,
which is prohibited under the Act.
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
15
A similar process would be required if critical habitat is designated. Federal agencies would
have to review their action for the effects on critical habitat, and would enter into section 7
consultation with us on actions they determine may affect critical habitat. That consultation
would result in a biological opinion as to whether the Proposed Action is likely to destroy or
adversely modify designated critical habitat, which is also prohibited under the Act.
Activities that would destroy or adversely modify critical habitat are defined as those actions that
"appreciably diminish the value of critical habitat for both the survival and recovery" of the
species (50 CFR 401.02). Activities that would jeopardize the continued existence of a species
are defined as those actions that "reasonably would be expected, directly or indirectly, to reduce
appreciably the likelihood of both the survival and recovery" of the listed species (50 CFR
402.02). Given the similarity of these definitions, activities that would likely destroy or
adversely modify critical habitat would also likely jeopardize the species when the action area is
occupied by Mexican spotted owl. Therefore, implementation of the Proposed Action would
result in no environmental consequences when compared to the No Action Alternative in
occupied areas.
Potential environmental consequences that may result from implementation of the No Action and
Proposed Actions are discussed below. All impacts are expected to be indirect, as critical habitat
designation does not in itself directly result in any alteration of the environment. Designation of
critical habitat may in some cases provide some benefits to a species by alerting Federal agencies
to situations when section 7 consultation is required. This may be particularly true in cases
where the action would not result in direct mortality, injury or harm to individuals of a listed
species (e.g., an action occurring within a critical habitat area when a species is not present).
Another potential benefit is that critical habitat may help to focus Federal, State, and private
conservation and management efforts. In areas which do not currently contain Mexican spotted
owls, critical habitat designation may have some effect in that it will require Federal agencies to
consult with us pursuant to section 7 of the Act, to insure their actions do not destroy or
adversely modify critical habitat. In the case of the owl, however, we are already consulting with
Federal agencies on activities that may affect the owl within the Recovery Units. Since the
proposed critical habitat units all occur within the Recovery Units, we do not anticipate any
additional impact due to designating potentially occupied habitat within the Recovery Units.
Federal agencies have been required to ensure that their actions do not jeopardize the continued
existence of the Mexican spotted owl since its listing in 1993. The prohibition against adverse
modification of critical habitat is not expected to impose any additional restrictions to those that
currently exist in areas of designated critical habitat.
As required by NEPA, this document is in part intended to disclose the programmatic goals and
objectives of the Act. These objectives include the protection of natural communities and
ecosystems, the minimization of fragmentation and the promotion of the natural patterns and
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
16
connectivity of wildlife habitats, the promotion of native species and the avoidance of the
introduction of non-native species, the protection of rare and ecologically important species and
unique or sensitive environments, the maintenance of naturally occurring ecosystem processes
and genetic and structural diversity, and the restoration of ecosystems, communities and the
recovery of species.
4.1 Effects on the Mexican Spotted Owl
The No Action Alternative would have no significant impacts to Mexican spotted owls in areas
presently occupied by the species because the protections resulting from their listing in 1993 and
the associated requirements of section 7 of the Act are already in place and are duplicative of
protections associated with critical habitat designation.
Implementation of the Proposed Action would provide protection under section 7 of the Act to
areas potentially occupied by the Mexican spotted owl, thus preserving recovery options for the
species. Designation of critical habitat would result in the requirement that any such activities be
reviewed for their effects on critical habitat and that review may result in measures to minimize
adverse effects. Implementation of the no action alternative would forego the opportunity to
provide such benefits.
Benefits to Mexican spotted owl that may accrue from designation of critical habitat would be
the requirement under section 7 of the Act that Federal agencies review their actions to assess
their effects on critical habitat. Federal actions that could possibly adversely affect Mexican
spotted owl habitat are further discussed in section 4.4 below. Designation of critical habitat
would result in the requirement that all Federal actions be reviewed for their effects on critical
habitat and that review may result in measures to minimize adverse effects.
4.2 Effect on Fish, Wildlife and Plants
The No Action alternative would have no significant impacts to fish, wildlife or plants beyond
those protections already in place as a result of listing of Mexican spotted owls in 1993 and
associated requirements of section 7 of the Act.
The objectives of designating critical habitat include the protection of natural communities and
ecosystems, the minimization of fragmentation and the maintenance and restoration of the
natural landscape patterns and connectivity of wildlife habitats, the promotion of native species
and the avoidance of the introduction of non-native species, the protection of rare and
ecologically important species and unique or sensitive environments, the maintenance of
naturally occurring ecosystem processes and genetic and structural diversity, and the restoration
of ecosystems, communities and the recovery of species.
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
17
In areas currently occupied by the Mexican spotted owl, fish, wildlife, and plants may indirectly
benefit as a result of ecosystem protections provided through the conservation of the owl and the
associated requirements of section 7 of the Act. Designation of critical habitat under the
Proposed Action in areas not currently occupied by the owl could provide similar ecological
benefits to fish, wildlife, and plants.
4.3 Recreational Impacts
The No Action alternative would have no impacts upon the continued use of the critical habitat
area for camping, hunting, and fishing beyond any impacts that resulted from the 1993 listing of
the Mexican spotted owl.
Implementation of the Proposed Action would help protect native ecosystems in Arizona,
Colorado, New Mexico, and Utah. The designated critical habitat is mostly composed of Federal
lands (e.g., National Forests, Bureau of Land Management, National Park Service, and National
Recreation Areas) that are managed, in part, for recreation. Neither alternative would impact the
continued recreational use of these areas.
4.4 Agricultural, Including Timber, Fuelwood, and Grazing Impacts
The No Action alternative would have no impacts upon agricultural activities including timber
harvesting and grazing beyond those already resulting from the listing of the 1993 listing of
Mexican spotted owls and the associated requirements of section 7 of the Act.
The implementation of the Proposed Action could potentially affect Federal activities or private
or other non-Federal activities. Under the Act, critical habitat may not be adversely modified by
a Federal agency action; critical habitat does not impose any restrictions on non-Federal persons
unless they are conducting activities funded or otherwise sponsored or permitted by a Federal
agency. The activities that could be affected are those that require a Federal action (permit,
authorization, or funding) and that involve such activities as removing or destroying Mexican
spotted owl habitat (as defined in the primary constituent elements discussion), whether by
mechanical or other means (e.g., timber harvest, right-of-way access, road construction,
development, etc.), including indirect effects that appreciably decrease habitat value or quality.
Federal activities that could be impacted are those that affect protected or restricted habitat by the
Forest Service, Bureau of Indian Affairs, Bureau of Land Management, Department of Defense,
Department of Energy, National Park Service, Federal Highway Administration, or Federal
Emergency Management Agency; vegetative management projects (including timber harvest,
timber salvage, and tree density control activities such as thinning, insect and disease suppression
activities, snag removal, and certain fire/ecosystem projects such as prescribed natural and
management ignited fire); livestock grazing in riparian habitat; land acquisition and disposal; oil
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
18
and gas development; mining and mineral exploration; military maneuvers; road development,
maintenance, and repair; utility construction and repair; construction of campgrounds and other
recreational developments; and access easements.
Actions not likely to destroy or adversely modify critical habitat include “personal use”
commodity production such as fuelwood, latilla and viga, Christmas tree cutting, and most
recreational activities including hiking, camping, fishing, hunting, cross-country skiing, off-road
vehicle use, and various activities associated with nature appreciation. The Service does not
expect any restrictions to those activities as a result of critical habitat designation.
4.5 Socioeconomic Impacts
The No Action alternative would have no impacts to the economic vitality of existing businesses
within the area, business districts, the local economy, tax revenues, public expenditures, or
municipalities beyond those impacts already resulting from the1993 listing of the Mexican
spotted owl and the associated requirements of section 7 of the Act.
The Proposed Action may have some socioeconomic impacts compared to the No Action
alternative if section 7 consultation on Federal actions in areas potentially occupied by the
Mexican spotted owl result in curtailment of those programs listed above (e.g., vegetative
management projects, livestock grazing, land acquisition and disposal; oil and gas development;
mining and mineral exploration, etc.) or other economic activity. Conversely, conservation of
natural ecosystems may provide economic benefits in attracting nature enthusiasts, such as bird
watchers, to the area.
Section 4(b)(2) of the Act requires us to designate critical habitat on the basis of the best
scientific and commercial information available and consider the economic and other relevant
impacts of designating a particular area as critical habitat. We based this designation on the best
available scientific information, including recommendations in the species' recovery plan. We
utilized the economic analysis and our analysis of other relevant impacts, and considered all
comments and information submitted during the public hearing and comment period, to make a
final critical habitat designation.
4.6 Direct and Indirect Effects
Designation of critical habitat in occupied areas is not anticipated to result in direct effects on the
components, structures, and functioning of canyon and forested habitats, or the aesthetic,
historic, economic, social, and health resources of the area, beyond those effects resulting from
the 1993 listing of Mexican spotted owl and associated requirements of section 7 of the Act.
However, at this time, the best available information leads us to conclude that there will be direct
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
19
impacts beyond those already associated with the species listing, in potentially occupied areas
designated as critical habitat. For example, designation of critical habitat in areas potentially
occupied by the owl could provide similar ecological benefits to fish, wildlife, and plants.
Furthermore, a designation of critical habitat will provide some educational benefit by formally
identifying on a range-wide basis those areas essential to the conservation of the species, and
thus, the areas likely to be the focus of our recovery efforts for the Mexican spotted owl.
Indirect effects of the designation that are reasonably foreseeable include focusing conservation
activities by identifying areas that are essential to the conservation of the species, regardless of
whether they are currently occupied by the listed species, thus alerting the public and land
managing agencies to the importance of an area to conservation. Similarly, critical habitat
designation may alert Federal agencies to situations requiring section 7 consultation. Therefore,
the possibility exists that private entities could be impacted if Federal actions are modified by the
designation of critical habitat. While we are unable to reliably estimate those impacts, they are
not expected to be significant.
4.7 Cumulative Impact
Designation of critical habitat for the Mexican spotted owl in presently occupied areas will have
no incremental impact when added to other past, present, and reasonably foreseeable future
actions within the canyon and forested habitats. In potentially occupied areas there may be some
impact on Federal activities. However, we expect this impact to be relatively small because in
addition to the Mexican spotted owl, the subject of the Proposed Action, several listed and
candidate species may occur in the action area. Some of these include the Gila trout, spikedace,
loach minnow, southwestern willow flycatcher, cactus ferruginous pygmy-owl, and the
threatened bald eagle. Federal agencies are required to ensure that any action they authorize,
fund, or carry out is not likely to jeopardize the continued existence of the listed species, or
destroy or adversely modify designated critical habitat in accordance with section 7(a)(2) of the
Act. Activities that adversely modify critical habitat are defined as those actions that
“appreciably diminish the value of critical habitat for both the survival and recovery” of the
species (50 CFR 401.02). Activities that jeopardize a species are defined as those actions that
“reasonably would be expected, directly or indirectly, to reduce appreciably the likelihood of
both the survival and recovery” of the listed species (50 CFR 402.02). According to these
definitions, activities that destroy or adversely modify critical habitat would ordinarily jeopardize
the species. Therefore, designation of critical habitat has very rarely resulted in greater
protection than that afforded under section 7 by the listing of a species. Section 7 consultations
apply only to actions with Federal involvement (i.e., activities authorized, funded, or conducted
by Federal agencies), and do not impact activities strictly under State or private authority.
In practice, the designation of critical habitat for the Mexican spotted owl will likely provide
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
20
little or no additional benefits to the species in presently occupied areas because there are
functioning program activities already alerting Federal agencies and the public of endangered
species concerns. However, there may be some benefits in potentially occupied habitat.
5.0 Council on Environmental Quality Analysis of Significance
Under CEQ 40 CFR Part 1508.27, the determination of “significantly” requires consideration of
both context and intensity.
5.1 Context: Based upon our responses from agencies and the public, although long-term, any
effects will not be national, only regional and mostly local in context; and any that occur are
expected to be small.
5.2 Intensity: Intensity is define by CEQ as referring to the severity of impact. The following
ten points identified by CEQ were considered in evaluating intensity.
1. Both beneficial and adverse impacts may occur as a result of this designation; most are
expected to be beneficial to the environment and any adverse societal impacts are expected to be
small.
2. This designation will not have a discernable impact on human safety. For example, some
commenters questioned whether this designation would cause delays in the Forest Service’s
ability to reduce the risk of catastrophic wildfire in a timely manner. The designation of critical
habitat likely will not require any additional restrictions for section 7 consultations, including
projects designed to reduce the risk of wildfire (e.g., prescribed burns, mechanical thinning, etc.).
3. Although several areas designated as critical habitat are in proximity to historic and cultural
sites, parklands, farmland, wetlands, scenic rivers and ecologically critical areas, no major
adverse impacts will occur to these areas; in fact, the ecologically critical areas are expected to
only benefit from this designation.
4. There is a perception by some segments of the public that critical habitat designation will
severely limit property rights; however, critical habitat designation has no effect on private
actions on private land that do not involve Federal approval or action. Therefore, we conclude
that this misperception will be clarified by the Final Rule and will result in this designation not
being highly controversial.
5. The Service has designated critical habitat for other species in the recent past and we are
familiar with the associated affects. Therefore, we do not anticipate any effects to the human
environment and we are highly certain this action does not involve any unique or unknown risks.
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
21
6. This designation of critical habitat is not expected to set any precedents for future actions with
significant effects or represent a decision in principle about a future consideration because
critical habitat has been designated before for other species, as required by law, often in close
proximity to or within the same lands involved in this designation.
7. This designation of critical habitat will be additive (cumulative) to critical habitat that has
been, and will be, designated for other species. However, it is the Service’s conclusion that the
beneficial and adverse impacts of any and all critical habitat designations are small, and therefore
insignificant, due to the existing impacts, both beneficial and adverse, already resulting from the
listing of the species involved.
8. This designation will have no adverse effects to National Register of Historic Places or other
cultural sites and it could possiblly benefit historic sites near forested areas due to focusing
conservation efforts on reducing the risk of catastrophic wildfire.
9. All impacts from this designation of critical habitat are certain to be totally beneficial to
endangered and threatened species, particularly the Mexican spotted owl.
10. This designation of critical habitat will not violate any Federal, state, or local laws or
requirements imposed for the protection of the environment.
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
22
REFERENCES CITED
Fletcher, K.W. 1990. Habitats used, abundance, and distribution of the Mexican Spotted Owl.
Unpub. Report U.S. Department of Agriculture, Forest Service, Region 3, Albuquerque,
New Mexico. 56 pp.
Fletcher, K.W, and Hollis, H.E. 1994. Habitats used, abundance, and distribution of the
Mexican Spotted Owl. Unpub. Report U.S. Department of Agriculture, Forest Service,
Region 3, Albuquerque, New Mexico. 86 pp.
Forsman, E.D. 1981. Molt of the spotted owl. Auk 98:735-742.
Ganey, J.L. 1988. Distribution and habitat ecology of Mexican spotted owls in Arizona. MS
Thesis. Northern Arizona University, Flagstaff, Arizona.
Ganey, J.L., and R.P. Balda. 1989a. Distribution and habitat use of Mexican spotted owls in
Arizona. Condor 91:355-361.
-----. 1994. Habitat selection by Mexican spotted owls in northern Arizona. Auk 111(1):162-
169.
Moen, C.A., A.B. Franklin, and R.J. Gutierrez. 1991. Age determination of subadult northern
spotted owls in northwestern California. Wildl. Soc. Bull. 19:489-493.
Seamans, M.E. and R.J. Gutiérrez. 1995. Breeding habitat of the Mexican spotted owl in the
Tularosa Mountains, New Mexico. Condor 97:944-952.
Skaggs, R.W., and R.J. Raitt. 1988. A spotted owl inventory of the Lincoln National Forest,
Sacramento Division, 1988. Share with Wildlife Program Contract No. 5-516.6-76-17.
New Mexico Department of Game and Fish, Santa Fe. 12 pp.
USDI Fish and Wildlife Service. 1991. Mexican spotted owl (Strix occidentalis lucida) Status
Review. Endangered species report 20. Albuquerque, New Mexico.
USDI Fish and Wildlife Service. 1993. Endangered and threatened wildlife and plants; final
rule to list the Mexican spotted owl as a threatened species. Federal Register 58:14248-
14271.
USDI Fish and Wildlife Service. 1995. Recovery plan for the Mexican spotted owl (Strix
occidentalis lucida). Albuquerque, New Mexico. 85pp.
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
23
USDI Fish and Wildlife Service. 1998. Endangered and Threatened Wildlife and Plants;
revocation of critical habitat for the Mexican spotted owl, loach minnow, and spikedace.
Federal Register 63:14378-14379.
USDI Fish and Wildlife Service. 2000. Endangered and Threatened Wildlife and Plants;
proposed designation of critical habitat for the Mexican spotted owl. Federal Register
65:45336-45353.
USDI Fish and Wildlife Service. 2000. Endangered and Threatened Wildlife and Plants;.
reopening of comment period on proposed critical habitat for the Mexican spotted owl;
availability of draft economic analysis and draft environmental assessment. Federal
Register 65:63047.
Ward, J.P. Jr., and W.M. Block. 1995. Mexican spotted owl prey ecology. In Mexican Spotted
Owl Recovery Plan. U.S. Department of the Interior, Fish and Wildlife Service,
Albuquerque, New Mexico.
Young, K.E., R. Valdez, P.J. Zwank, and W.R. Gould. 1998. Density and roost site
characteristics of spotted owls in Sierra Madre Occidental, Chihuahua, Mexico. Condor
100:732-736.

Click tabs to swap between content that is broken into logical sections.

ENVIRONMENTAL ASSESSMENT
DESIGNATION OF CRITICAL HABITAT
FOR THE
MEXICAN SPOTTED OWL
(Strix occidentalis lucida)
Prepared by
U.S. Fish and Wildlife Service
New Mexico Ecological Services Field Office
Albuquerque, New Mexico
TABLE OF CONTENTS
1.0 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Need for the Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Critical Habitat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.0 Description of Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 No Action Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Action Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.1 Designation Identified in the Final Rule (Proposed Action) . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.2 Designation Identical to the 1995 Final Rule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.3 Designation of the Entire Historical Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.4 Designation of Only the Occupied Portions of Historical Range . . . . . . . . . . . . . . . . . . 10
3.0 Description of the Affected Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1 Physical and Biological Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2 Human Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.3 Tribal Lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.0 Environmental Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.1 Effects on Mexican Spotted Owl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.2 Effect on Fish, Wildlife and Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.3 Recreational Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.4 Agricultural, Including Timber, Fuelwood, and Grazing Impacts . . . . . . . . . . . . . . . . . . 17
4.5 Socioeconomic Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.6 Direct and Indirect Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.7 Cumulative Impact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.0 Council on Environmental Quality Analysis of Significance . . . . . . . . . . . . . . . . . . . . . . . . 20
References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
ENVIRONMENTAL ASSESSMENT
DESIGNATION OF CRITICAL HABITAT FOR MEXICAN SPOTTED OWL
1.0 Purpose
The purpose of designating critical habitat for the threatened Mexican spotted owl (Strix
occidentalis lucida) is to utilize provisions of the Endangered Species Act of 1973, as amended
(Act), to help achieve the species’ conservation. The purpose of the Act is to conserve the
ecosystems upon which endangered and threatened species depend. Critical habitat designation
identifies those areas that are essential to the survival and recovery of the Mexican spotted owl,
and describes those physical and biological features within those areas that require special
management considerations to achieve conservation of the species.
1.1 Need for the Action
The need for this action is to comply with section 4 of the Act, which requires that critical habitat
be designated for endangered and threatened species unless such designation is not prudent. In
the final rule listing the Mexican spotted owl as a threatened (58 FR 14248), we, the Fish and
Wildlife Service, found that although considerable knowledge of owl habitat needs had been
gathered in recent years, habitat maps in sufficient detail to accurately delineate critical habitat
areas were not available. After the listing, we began gathering the data necessary to develop a
proposed rule to designate critical habitat. A final rule designating critical habitat for the
Mexican spotted owl was published on June 6, 1995 (60 FR 29914). In 1996, the Tenth Circuit
Court of Appeals in Catron County Board of Commissioners v. United States Fish and Wildlife
Service, 75 F.3d 1429, 1439 (10th Cir. 1996), ruled that the Service had to comply with the
National Environmental Policy Act (NEPA) before designating critical habitat for two desert
fish, the spikedace and loach minnow. In addition, a federal district court in New Mexico later
set aside the final rule designating critical habitat for the owl and forbid the Service from
enforcing critical habitat for the owl (Coalition of Arizona-New Mexico Counties for Stable
Economic Growth v. U.S. Fish and Wildlife Service, No. 95-1285-M Civil, April 1, 1997). As a
result of these court rulings, we removed the critical habitat designation for the owl from the
Code of Federal Regulations on March 25, 1998 (63 FR 14378).
On March 13, 2000, the United States District Court for the District of New Mexico, (Southwest
Center for Biological Diversity and Silver v. Babbitt and Clark, CIV 99-519 LFG/LCS-ACE),
ordered us to propose critical habitat within 4 months of the court order, and to complete and
publish a final designation of critical habitat for the Mexican spotted owl by January 15, 2001.
On July 21, 2000, we published a proposal to designate critical habitat for the Mexican spotted
owl in Arizona, Colorado, New Mexico, and Utah, mostly on Federal lands (65 FR 45336). This
final rule is in response to that court order. Critical habitat is one of several provisions of the
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
2
ESA that aid in protecting the habitat of listed species until populations have recovered and
threats have been minimized so that the species can be removed from the list of threatened and
endangered species. Critical habitat designation is intended to assist in achieving long-term
protection and recovery of Mexican spotted owls and the ecosystems upon which they depend,
by subjecting areas designated as critical habitat to section 7(a)(2) of the Act, thereby requiring
consultation for Federal actions that may affect these areas in order to avoid destruction or
adverse modification of this habitat. Further explanation of critical habitat and its
implementation is provided below.
1.2 Background
The Mexican spotted owl (Strix occidentalis lucida) is one of three subspecies of spotted owl
occurring in the United States; the other two are the northern spotted owl (S. o. caurina) and the
California spotted owl (S. o. occidentalis). The Mexican spotted owl is distinguished from the
California and northern subspecies chiefly by geographic distribution and plumage. The
Mexican spotted owl is mottled in appearance with irregular white and brown spots on its
abdomen, back, and head. The spots of the Mexican spotted owl are larger and more numerous
than in the other two subspecies, giving it a lighter appearance.
The Mexican spotted owl has the largest geographic range of the three subspecies. The range
extends north from Aguascalientes, Mexico, through the mountains of Arizona, New Mexico,
and western Texas, to the canyons of Utah and Colorado, and the Front Range of central
Colorado. Much remains unknown about the species' distribution in Mexico, where much of the
owl's range has not been surveyed. The owl occupies a fragmented distribution throughout its
United States range, corresponding to the availability of forested mountains and canyons, and in
some cases, rocky canyonlands. Although there are no estimates of the owl’s historical
population size, its historical range and present distribution are thought to be similar.
According to the Recovery Plan for the Mexican Spotted Owl (United States Department of
Interior 1995) (Recovery Plan), 91 percent of owls known to exist in the United States between
1990 and 1993 occurred on land administered by the U.S. Forest Service (FS); therefore, the
primary administrator of lands supporting owls in the United States is the FS. These numbers are
based upon preliminary surveys that were focused on National Forests in the southwest.
Nevertheless, most owls have been found within Region 3 of the FS, which includes 11 National
Forests in New Mexico and Arizona. FS Regions 2 and 4, including two National Forests in
Colorado and three in Utah, support fewer owls. The range of the owl is divided into 11
Recovery Units (RU), 5 in Mexico and 6 in the United States, as identified in the Recovery Plan.
The Recovery Plan also identifies recovery criteria and provides distribution, abundance, and
density estimates by RU. Of the RUs in the United States, the Upper Gila Mountains RU,
located in the central portion of the species’ U.S. range in central Arizona and west-central New
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
3
Mexico, contains over half of known owl sites. Owls here use a wide variety of habitat types,
but are most commonly found inhabiting mature mixed-conifer and ponderosa pine-Gambel oak
forests. The Basin and Range-East RU encompasses central and southern New Mexico, and
includes numerous parallel mountain ranges separated by alluvial valleys and broad, flat basins.
Most breeding spotted owls occur in mature mixed-conifer forest. The Basin and Range-West
RU contains mountain ranges separated by non-forested habitat. These “sky island” mountains
of southern Arizona and far-western New Mexico contain mid-elevation mixed-conifer forest and
lower elevation Madrean pine-oak woodlands that support spotted owls. The Colorado Plateau
RU includes northern Arizona, southern Utah, southwestern Colorado, and northwestern New
Mexico, with owls generally confined to deeply incised canyon systems and wooded areas of
isolated mountain ranges. The Southern Rocky Mountains-New Mexico RU consists of the
mountain ranges of northern New Mexico. Owls in this unit typically inhabit mature mixed-conifer
forest in steep canyons. The smallest number of spotted owls occurs in the Southern
Rocky Mountains-Colorado RU. This unit includes the southern Rocky Mountains in Colorado,
where spotted owls are largely confined to steep canyons, generally with significant rock faces
and various amounts of mature coniferous forest. The critical habitat units identified in this
designation are all within these RUs.
A reliable estimate of the numbers of owls throughout its entire range is not currently available.
Using information gathered by Region 3 of the FS, Fletcher (1990) calculated that 2,074 owls
existed in Arizona and New Mexico in 1990. Based on more up-to-date information, we
subsequently modified Fletcher’s calculations and estimated a total of 2,160 owls throughout the
United States (USDI 1991). However, these numbers are not considered reliable estimates of
current population size for a variety of statistical reasons, and a pilot study (Ganey et al. 1999)
conducted in 1999 estimated the number of owls for the upper Gila Mountains Recovery Unit
(exclusive of tribal lands) as 2,950 (95 percent confidence interval 717-5,183).
Mexican spotted owls nest, roost, forage, and disperse in a diverse array of biotic communities.
Nesting habitat is typically in areas with complex forest structure or rocky canyons, and contains
uneven-aged, multi-storied mature or old-growth stands that have high canopy closure (Ganey
and Balda 1989, USDI 1991). In the northern portion of the range (Utah and Colorado), most
nests are in caves or on cliff ledges in steep-walled canyons. Elsewhere, the majority of nests
appear to be in Douglas fir (Pseudotsuga menziesii) trees (Fletcher and Hollis 1994, Seamans
and Gutierrez 1995). A wide variety of tree species is used for roosting; however, Douglas fir is
the most commonly used species in mixed conifer forests (Ganey 1988, Fletcher and Hollis
1994, Young et al. 1998). Owls generally use a wider variety of forest conditions for foraging
than they use for nesting/roosting.
Seasonal movement patterns of Mexican spotted owls are variable. Some individuals are year-round
residents within an area, some remain in the same general area but show shifts in habitat
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
4
use patterns, and some migrate considerable distances (20-50 kilometers (km)) (12-31 miles
(mi)) during the winter, generally migrating to more open habitat at lower elevations (Ganey and
Balda 1989b, Willey 1993, Ganey et al.1998). The home-range size of Mexican spotted owls
appears to vary considerably among habitats and/or geographic areas (USDI 1995), ranging in
size from 261-1,487 ha (647-3,688 ac) for individuals birds, and 381-1,551 ha (945-3,846 ac) for
pairs (Ganey and Balda 1989b, Ganey et al. 1999). Little is known about habitat use by juveniles
dispersing soon after fledging. Ganey et al. (1998) found dispersing juveniles in a variety of
habitats ranging from high-elevation forests to piñon-juniper woodlands and riparian areas
surrounded by desert grasslands.
Mexican spotted owls do not nest every year. The owl’s reproductive pattern varies somewhat
across its range. In Arizona, courtship usually begins in March with pairs roosting together
during the day and calling to each other at dusk (Ganey 1988). Eggs are typically laid in late
March or early April. Incubation begins shortly after the first egg is laid, and is performed
entirely by the female (Ganey 1988). The incubation period is about 30 days (Ganey 1988).
During incubation and the first half of the brooding period, the female leaves the nest only to
defecate, regurgitate pellets, or receive prey from the male, who does all or most of the hunting
(Forsman et al. 1984, Ganey 1988). Eggs usually hatch in early May, with nestling owls
fledging 4 to 5 weeks later, and then dispersing in mid-September to early October (Ganey
1988).
Little is known about the reproductive output for the spotted owl. It varies both spatially and
temporally (White et al. 1995), but the subspecies demonstrates an average annual rate of about
one young per pair. Based on short-term population and radio tracking studies, and longer-term
monitoring studies, the probability of an adult owl surviving from 1 year to the next is 80 to 90
percent. Average annual juvenile survival is considerably lower, at 6 to 29 percent, although it is
believed these estimates may be artificially low due to the high likelihood of permanent dispersal
from the study area, and the lag of several years before marked juveniles reappear as territory
holders and are detected as survivors through recapture efforts (White et al. 1995). Little
research has been conducted on the causes of mortality, but predation by great horned owls
(Bubo virginianus), northern goshawks (Accipter gentilis), red-tailed hawks (Buteo jamaicensis),
and golden eagles (Aquila chrysaetos), as well as starvation, and collisions (e.g., with cars,
powerlines), may all be contributing factors.
Mexican spotted owls consume a variety of prey throughout their range, but commonly eat
small- and medium-sized rodents such as woodrats (Neotoma spp.), peromyscid mice
(Peromyscus spp.), and microtine voles (Microtus spp.). Owls also may consume bats, birds,
reptiles, and arthropods (Ward and Block 1995). Each prey species uses a unique habitat, so that
the differences in the owl’s diet across its range likely reflect geographic variation in population
densities and habitats of both the prey and the owl (Ward and Block 1995). Deer mice (P.
maniculatus) are widespread in distribution in comparison to brush mice (P. boylei), which are
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
5
restricted to drier, rockier substrates, with sparse tree cover. Mexican woodrats (N. mexicana)
are typically found in areas with considerable shrub or understory tree cover and high log
volumes or rocky outcrops. Mexican voles (M. mexicanus) are associated with high herbaceous
cover, primarily grasses, whereas long-tailed voles (M. longicaudus) are found in dense
herbaceous cover, primarily forbs, with many shrubs and limited tree cover.
Two primary reasons were cited for listing the owl as threatened in 1993: (1) historical alteration
of its habitat as the result of timber management practices, specifically the use of even-aged
silviculture, and the threat of these practices continuing; and (2) the danger of catastrophic
wildfire. The Recovery Plan for the owl outlines management actions that land management
agencies and Indian tribes should undertake to remove recognized threats and recover the spotted
owl. This critical habitat designation is based on recovery needs and guidelines identified in the
Recovery Plan.
1.3 Critical Habitat
Critical habitat is defined in section 3(5)(A) of the Act as – (i) the specific areas within the
geographical area occupied by a species, at the time it is listed in accordance with the Act, on
which are found those physical or biological features (I) essential to the conservation of the
species and (II) that may require special management considerations or protection; and (ii)
specific areas outside the geographical area occupied by a species at the time it is listed, upon a
determination that such areas are essential for the conservation of the species. The term
"conservation," as defined in section 3(3) of the Act, means "the use of all methods and
procedures which are necessary to bring an endangered species or threatened species to the point
at which the measures provided pursuant to this Act are no longer necessary" (i.e., the species is
recovered and removed from the list of endangered and threatened species).
Section 4(b)(2) of the Act requires that we base critical habitat designation on the best scientific
and commercial data available, taking into consideration the economic impact, and any other
relevant impact, of specifying any particular area as critical habitat. We may exclude areas from
critical habitat designation if we determine that the benefits of exclusion outweigh the benefits of
including the areas as critical habitat, provided the exclusion will not result in the extinction of
the species. We are also required to consider those habitat features (primary constituent
elements) that provide for the physiological, behavioral, and ecological requirements essential
for the conservation of the species and that may require special management considerations or
protection. Such physical and biological features, as outlined in 50 CFR 424.12, include, but are
not limited to, the following:
(1) Space for individual and population growth, and for normal behavior;
(2) Food, water, or other nutritional or physiological requirements;
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
6
(3) Cover or shelter;
(4) Sites for breeding, reproduction, or rearing of offspring; and
(5) Habitats that are protected from disturbances or are representative of the historic
geographical and ecological distribution of a species.
2.0 Description of Alternatives
The Service considered the No Action Alternative as required by NEPA. The Action Alternative
is to designate critical habitat as ordered by the court.
2.1 No Action Alternative
The No Action alternative is defined as a decision to forgo the designation of critical habitat for
the Mexican spotted owl. This alternative serves to delineate the existing environment and
conditions that are anticipated to result from the listing of the species, without designation of
critical habitat. Since the listing of the species as threatened, the Mexican spotted owl has been
protected under section 7 of the Act by prohibiting Federal agencies from implementing actions
that would jeopardize the continued existence of the species. This protection under the Act is
considered the baseline against which we evaluate the action alternatives described below.
2.2 Action Alternatives
The Action Alternatives each would include designation of critical habitat in areas believed to
contain the physical and biological features upon which the Mexican spotted owl depends. The
Act refers to these essential habitat features as “primary constituent elements.” We determined
the primary constituent elements for Mexican spotted owl from studies of their habitat
requirements and the information provided in the Recovery Plan (USDI 1995 and references
therein). Since owl habitat can include both canyon and forested areas, we identified primary
constituent elements in both areas. Within restricted habitat (described in the Recovery Plan,
Volume I, part III, pages 84-95, including Table III.B.1), mixed conifer, pine-oak, and riparian
forest types that currently contain or may attain the habitat attributes believed capable of
supporting nesting and roosting owls include:
- high basal area of large diameter trees;
- moderate to high canopy closure;
- wide range of tree sizes suggestive of uneven-age stands;
- multi-layered canopy with large overstory trees of various species;
- high snag basal area;
- high volumes of fallen trees and other woody debris;
- high plant species richness, including hardwoods; and
- adequate levels of residual plant cover to maintain fruits, seeds, and regeneration to
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
7
provide for the needs of Mexican spotted owl prey species.
For canyon habitat, the primary constituent elements include the following attributes:
- cooler and often more humid conditions than the surrounding area;
- clumps or stringers of trees and/or canyon wall containing crevices, ledges, or caves;
- high percent of ground litter and woody debris; and
- riparian or woody vegetation (although not at all sites).
The forest habitat attributes listed above usually develop with increasing forest age, but their
occurrence may vary by location, past forest management practices or natural disturbance events,
forest type, and productivity. These characteristics may also develop in younger stands,
especially when the stands contain remnant large trees or patches of large trees from earlier
stands. Certain forest management practices may also enhance tree growth and mature stand
characteristics where the older, larger trees are allowed to persist.
Canyon habitats used for nesting and roosting are typically characterized by cooler conditions
found in steep, narrow canyons, often containing crevices, ledges, and/or caves. These canyons
frequently contain small clumps or stringers of ponderosa pine, Douglas fir, white fir, and/or
piñon-juniper. Deciduous riparian and upland tree species may also be present. Adjacent
uplands are usually vegetated by a variety of plant associations including piñon-juniper
woodland, desert scrub vegetation, ponderosa pine-Gambel oak, ponderosa pine, or mixed
conifer. Owl habitat may also exhibit a combination of attributes between the forested and
canyon types.
2.2.1 Designation as identified in the Final Rule
Our preferred alternative is to finalize the designation of critical habitat as described in the final
rule signed on January 16, 2001, and becoming effective 30 days following publication in the
Federal Register. In developing this alternative, we reviewed the overall approach to the
conservation of the species since the species’ listing in 1993 (58 FR 14248); examined the
critical habitat units identified in the previous proposed (59 FR 63162) and final critical habitat
rules (60 FR 29914); considered new location data and habitat requirements for recovery and
definitions described in the Recovery Plan (USDI 1995), and information received during the
comment periods for the proposed rule (65 FR 45336; 65 FR 63047). All protected and
restricted habitat as described in the Recovery Plan is designated as critical habitat. The critical
habitat designation does not include tribal lands; FS lands within Arizona and New Mexico; Fort
Carson, Colorado; and low-density areas. However, the critical habitat designation does include
FS lands in Utah and Colorado, and other Federal lands in Arizona, New Mexico, Colorado, and
Utah, used by currently known populations of Mexican spotted owls. In addition, we included
areas where owls could occur based on the presence of the appropriate topography, elevation, and
habitat types (protected and restricted habitat areas as defined in the Recovery Plan).
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
8
All areas designated as critical habitat for the Mexican spotted owl are within the geographical
area occupied or potentially occupied by the Mexican spotted owl, in accordance with section
3(5)(A)(i) of the Act, which provides that areas outside the geographical area occupied by the
species may meet the definition of critical habitat upon determination that they are essential for
the conservation of the species. It is essential to protect all designated occupied areas as well as
potentially occupied areas that will provide habitat for recovery of this species.
The designated critical habitat constitutes our best assessment of areas needed for the
conservation of the owl and is based on the best scientific and commercial information available.
The areas are essential to the conservation of the species because they either currently support
populations of the owl, or because they currently possess the necessary habitat requirements for
nesting, roosting, and foraging (see description of primary constituent elements). Existing
human-constructed features and structures within designated critical habitat (e.g., buildings,
roads, etc.) do not contain Mexican spotted owl habitat and are not considered critical habitat.
Some units that were proposed as critical habitat were significantly reduced within Arizona and
New Mexico because of the exclusion of FS lands. Nevertheless, the remaining Federal lands
(e.g., Bureau of Land Management (BLM), National Park Service, etc.) within the mapped
boundaries in Arizona and New Mexico, are designated as critical habitat. The critical habitat
designation on Federal lands adjacent to FS lands within Arizona and New Mexico will ensure
that “special management considerations or protections” are provided for the Mexican spotted
owl on all Federal lands, pursuant to the definition of critical habitat in section 3 of the Act. We
did not designate some areas that are known to have widely scattered owl sites, low population
densities, and/or marginal habitat quality, which are not considered to be essential to this species’
survival or recovery.
State and private lands are not included in this designation. The overwhelming majority of
Mexican spotted owl records are from Federal and tribal lands, indicating that those lands are
essential to the species’ recovery. However, we did not include tribal lands or National Forest
lands within Arizona and New Mexico in the designation because we determined that the
management of the Mexican spotted owl on those lands with appropriate habitat management
plans provides substantial protection and that designation of critical habitat would provide little
or no additional benefit to the species.
2.2.2 Designation identical to the 1995 Final Rule
The 1995 final rule designating critical habitat for the Mexican spotted owl was based on the
proposed critical habitat designation published in 1994 (59 FR 63162). The previous critical
habitat designation was based on extensive use and evaluation of owl habitat and territory maps,
vegetation maps, aerial photography, and field verification to identify areas for designation as
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
9
critical habitat. Several qualitative criteria (including currently suitable habitat, large contiguous
blocks of habitat, occupied habitat, range wide distribution, the need for special management or
protection, adequacy of existing regulatory mechanisms) were considered when identifying
critical habitat areas. The 1995 critical habitat designation was published prior to the completion
of the Recovery Plan for the Mexican spotted owl and was based on information that was current
at that time. As a result of several court rulings, as discussed in section 1.1 of this document, we
removed the critical habitat designation for the owl from the Code of Federal Regulations on
March 25, 1998 (63 FR 14378).
Five years have passed since the 1995 critical habitat designation and there have been substantial
changes in the information available. Therefore, a designation of critical habitat that included
only those areas proposed in 1994 and finalized in 1995, would not conform to the requirement
of the Endangered Species Act to consider the best available scientific and commercial
information in designation of critical habitat. In addition, there have been substantial changes in
policy and court interpretations of critical habitat that require consideration of areas not included
in the 1995 designation. For the above reasons, this alternative was not considered to be viable
and will not be analyzed further.
2.2.3 Designation of the Entire Historical Range
We considered proposing to designate the entire historical range of the Mexican spotted owl,
which would include all areas where owls have been known to occur. In addition to the critical
habitat units identified in the proposed rule (65 FR 45336), areas such Dinosaur National Park in
northwest Colorado; Mesa Verde National Park, Ute Mountain Ute Reservation, Southern Ute
Reservation, other Forest Service and Bureau of Land Management land in southwest Colorado;
and the Guadalupe and Davis Mountains in southwest Texas would be included, as well as State
and private lands within the critical habitat boundaries. All areas that are known to have widely
scattered owl sites, low population densities, and/or marginal habitat quality, which are not
considered to be essential to this species' survival or recovery, would be included in this
alternative. Given that the majority of the owl’s range occurs on Federal and tribal lands, State
and private lands are not considered essential to the recovery of the species and therefore are not
designated as critical habitat. Exclusion of State, private, and some tribal lands from the
designation will not result in extinction or slow recovery of this species. Additionally, much of
these lands do not meet part (5)(A)(i)(I) of the definition of critical habitat stated above; we are,
therefore, not designating those lands as critical habitat. As a result, this alternative was removed
from further consideration because we concluded that the Proposed Action of designating 1.9
million hectares (ha) (4.6 million acres (ac)) of Federal lands, is sufficient to provide for the
survival and recovery of the species within all major segments of the owls historical range.
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
10
2.2.4 Designation of Only The Occupied Portions of the Historical Range
We considered only including those areas currently known to be occupied. The Service believes
the occupied and potentially occupied areas included in the final designation of critical habitat,
signed on January 16, 2001, and becoming effective 30 days following publication in the Federal
Register, are needed for the conservation of the Mexican spotted owl and that recovery of the
species will require all of these areas. Omission of any critical habitat unit may result in loss of
significant genetic and geographic components of the species, unless those lands provide “special
management considerations or protections” for the Mexican spotted owl, pursuant to the
definition of critical habitat in section 3 of the Act. If “special management considerations or
protections” are not provided and lands are excluded from the designation, the value of critical
habitat in those areas would be undermined in terms of size, connectivity, and habitat and
community diversity. No viable alternative exists if portions of the critical habitat in the
Proposed Action are omitted; thus, this alternative was not considered viable.
3.0 Description of the Affected Environment
The geographic area for the Proposed Action includes the portions of canyon and montane forest
habitats across a range that extends from southern Utah and the front range of Colorado, through
Arizona and New Mexico. We designated approximately 1.9 million hectares (ha) (4.6 million
acres (ac)) of critical habitat in Arizona, Colorado, New Mexico, and Utah, on Federal lands that
are composed of a combination of protected and restricted habitat within forested and canyon
habitat types.
3.1. Physical and Biological Environment
The Mexican spotted owl occupies a broad geographic area, largely restricted to montane forests
and canyons. The owl occurs in disjunct localities, corresponding to isolated mountain ranges
and canyons (USDI 1995). These forested mountain ranges and canyons encompass a wide array
of physical, climatic, and habitat features. The range of the owl is divided into 11 Recovery
Units (RU), 5 in Mexico and 6 in the United States, as identified in the Recovery Plan (USDI
1995). Only those RUs within the United States are included in this designation. The Recovery
Plan identified these RUs based on the following considerations (in order of importance: 1)
physiographic province, 2) biotic regimes, 3) perceived threats, 4) administrative boundaries, and
5) known patterns of owl distribution. The four major physiographic provinces that were used in
delineating the RUs in the United States are the Colorado Plateau, Basin and Range, Southern
Rocky Mountains, and Upper Gila Mountains.
The vegetative communities and structural attributes used by the owl vary across the designated
critical habitat. They are composed primarily of warm-temperate and cold-temperate forests,
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
11
and, to a lesser extent, woodlands and riparian deciduous forests. The mixed-conifer community
appears to be frequently used throughout most portions of the owl’s range (Skaggs and Raitt
1988; Ganey and Balda 1989, 1994; Service 1995). Mixed-conifer forests contain several
species of overstory trees. The most common are white fir (Abies concolor), Douglas fir
(Pseudotsuga menziesii), and ponderosa pine (Pinus ponderosa). Less common species are
southwestern white pine (P. strobiformis), limber pine (P. flexilis), aspen (Populus tremuloides),
and corkbark fir (Abies lasiocarpa var. arizonica). The understory within mixed-conifer
communities provides important roosting sites for Mexican spotted owls. The understory usually
contains the same conifer species found in the overstory, with Gambel oak (Quercus gambelii),
maples (Acer grandidentatum and A. glabrum), and New Mexico locust (Robinia neomexicana)
also present. Montane riparian canyon bottoms used by owls in the mixed-conifer zone may
contain box elder (Acer negundo), narrowleaf cottonwood (Populus angustifolia), maples (Acer
spp.), and alders (Alnus spp.).
Mexican spotted owls nest, roost, forage, and disperse in a diverse array of biotic communities.
Nesting habitat is typically in areas with complex forest structure or rocky canyons, and contains
uneven-aged, multi-storied mature or old-growth stands that have high canopy closure (Ganey
and Balda 1989, USDI 1991). In the northern portion of the range (southern Utah and Colorado),
most nests are in caves or on cliff ledges in steep-walled canyons. Elsewhere, the majority of
nests appear to be in Douglas fir trees (Fletcher and Hollis 1994; Seamans and Gutierrez 1995).
A wider variety of tree species is used for roosting; however Douglas fir is the most commonly
used species (Ganey 1988, Fletcher and Hollis 1994, Young et al 1998). Spotted owls generally
use a wider variety of forest conditions (mixed conifer, pine-oak, ponderosa pine, piñon-juniper)
for foraging than they use for nesting/roosting. Canyon habitats used for nesting and roosting are
typically characterized by the cooler conditions found in steep, narrow canyons, often containing
crevices, ledges, and/or caves. These canyons frequently contain small clumps or stringers of
ponderosa pine, Douglas fir, white fir, and/or pinon-juniper. Deciduous riparian and upland tree
species may also be present. Adjacent uplands are usually vegetated by a variety of plant
associations including pinon-juniper woodland, desert scrub vegetation, ponderosa pine-Gambel
oak, ponderosa pine, or mixed conifer.
Mexican spotted owls consume a variety of prey throughout their range, but commonly eat
small- and medium-sized rodents such as woodrats (Neotoma spp.), peromyscid mice
(Peromyscus spp.), and microtine voles (Microtus spp.). Owls also may consume bats, birds,
reptiles, and arthropods (Ward and Block 1995). Each prey species uses a unique habitat, so that
the differences in the owl’s diet across its range likely reflect geographic variation in population
densities and habitats of both the prey and the owl (Ward and Block 1995). Deer mice (P.
maniculatus) are widespread in distribution in comparison to brush mice (P. boylei), which are
restricted to drier, rockier substrates, with sparse tree cover. Mexican woodrats (N. mexicana)
are typically found in areas with considerable shrub or understory tree cover and high log
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
12
volumes or rocky outcrops. Mexican voles (M. mexicanus) are associated with high herbaceous
cover, primarily grasses, whereas long-tailed voles (M. longicaudus) are found in dense
herbaceous cover, primarily forbs, with many shrubs and limited tree cover.
The Mexican Spotted Owl Recovery Plan provides for three levels of habitat management:
protected areas, restricted areas, and other forest and woodland types. Protected habitat includes
all known owl sites, all areas within mixed conifer or pine-oak types with slopes greater than 40
percent where timber harvest has not occurred in the past 20 years, and all reserved lands
(designated Wilderness or other legally or administratively reserved areas). The Recovery Plan
recommends that protected areas, or Protected Activity Centers (PACs), be designated around
known owl sites. A PAC would include an area of at least 243 ha (600 ac) that includes the best
nesting and roosting habitat in the area. Based on available data, the recommended size for a
PAC includes, on average, 75 percent of the foraging area of an owl.
Restricted habitat includes mixed conifer forest, pine-oak forest, and riparian areas outside of
protected areas described above (i.e., areas that do not currently contain owls). These areas are
essential to the conservation of the species because the Recovery Plan identifies these areas as
providing additional owl habitat for future occupancy. All restricted habitat is designated as
critical habitat and has or is capable of having one or more of the primary constituent elements.
Other forest and woodland types (ponderosa pine, spruce-fir, piñon-juniper, and aspen) are not
expected to provide nesting or roosting habitat for the Mexican spotted owl (except when
associated with rock canyons). Thus, these other forest and woodland types are not considered to
be critical habitat unless specifically delineated within PACs. Although the Recovery Plan does
not provide owl-specific guidelines to managing these areas, these and other habitat types may
provide important foraging and dispersal habitat for the owl, particularly if adjacent to protected
or restricted areas. Therefore, these areas should be managed for landscape diversity, mimicking
natural disturbance patterns, incorporating natural variation in stands, and retaining special
features such as snags and large trees (USDI 1995).
3.2 Human Environment
There is a wide diversity of human activities and land uses throughout or adjacent to the areas
designated as critical habitat in Arizona, Colorado, New Mexico, and Utah. Uses include timber
harvest, personal use commodities (fuelwood, vigas, latillas), livestock grazing, fire management
activities, oil and gas leases, sand and gravel extraction, mining, military maneuvers, road
development, utility corridors, hydroelectric facilities, geothermal development, and a wider
variety of recreational activities.
The designation of critical habitat directly affects only Federal agencies. The Act requires
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
13
Federal agencies to ensure that actions they fund, authorize, or carry out do not destroy or
adversely modify critical habitat to the extent that the action appreciably diminishes the value of
the critical habitat for the survival and recovery of the species. Individuals, organizations, States,
local and Tribal governments, and other non-Federal entities are only affected by the designation
of critical habitat if their actions occur on Federal lands, require a Federal permit, license, or
other authorization, or involve Federal funding.
Although there are many parcels of State and private lands within the critical habitat boundaries,
these lands are not considered critical habitat. Given that the majority of the owl’s range occurs
on Federal and tribal lands, we do not feel that State and private lands are essential to the
recovery of the subspecies and should not be designated as critical habitat.
3.3 Tribal lands
Several tribes are located within the geographical area occupied by the Mexican spotted owl.
Each tribe is a sovereign entity, with its own government and community. There is a unique and
distinctive political relationship between the United States and Native American governments, as
defined by treaties, statutes, court decisions, and the Constitution, that differentiate Native
American governments from other interests and constituencies, and that relationship extends to
all Federal governments.
In our 1994 critical habitat proposal for the owl, we identified lands of the White Mountain
Apache, Jicarilla Apache, Mescalero Apache, San Carlos Apache, Southern Ute, Ute Mountain
Ute, and Navajo Nation Tribes as containing habitat that may be appropriate for designation of
critical habitat. The Proposed Action included lands of the Mescalero Apache, San Carlos
Apache, and Navajo Nation that are currently known to support owls. However, after
reevaluating the available data, we no longer feel that designating these areas is appropriate. As
provided under section 4(b)(2) of the Act, we solicited information on the possible economic and
other impacts of critical habitat designation, and continued to work with the tribes in developing
voluntary measures adequate to conserve Mexican spotted owls on tribal lands. During the
second comment period, the Mescalero Apache and Navajo Nation completed management plans
for the Mexican Spotted Owl. The San Carlos Apache Reservation management plan is
substantially complete and is expected to be completed in March of 2001. We reviewed a draft
of their plan and found it to be consistent with the Recovery Plan. We determined that adequate
special management is being provided for the Mexican spotted owl on the Navajo Nation and
Mescalero Apache lands and, therefore, they were not included in the designation since they do
not meet the definition of critical habitat. In the case of the San Carlos Apache Reservation we
found, in accordance with section 4(b)(2) of the Act, that the benefits of excluding their lands
outweighed the benefits of including them in the designation. We reviewed each of these plans
and determined that the management of the Mexican spotted owl will provide substantial
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
14
protection for the relevant habitat areas, and that designation of critical habitat will provide little
or no additional benefit to the species, particularly since all the areas are presently occupied by
the owl. More importantly, designation of critical habitat would be expected to adversely impact
our working relationship with the tribes and we believe that Federal regulation through critical
habitat designation would be viewed as an unwarranted and unwanted intrusion into tribal natural
resource programs. Our working relationship with the tribes has been extremely beneficial in
implementing natural resource programs of mutual interest.
During our review of the Navajo Nation management plan for the Mexican spotted owl, we
concluded that there is a unique land ownership of Navajo National Monument and Canyon de
Chelly, wherein the land is owned by the Navajo Nation, but under the management authority
and administration of the National Park Service. Although other lands owned by the Navajo
Nation were excluded from critical habitat, critical habitat was designated on Navajo National
Monument and Canyon de Chelly, because the National Park Service retains management
authority over these lands, and any management that may have the potential to adversely affect
the owl or its critical habitat would stem from their actions.
Since our previous critical habitat designation, we learned that the Southern Ute Reservation has
not supported spotted owls historically, and our assessment revealed that the Reservation does
not support habitat essential to the species' conservation. Thus, lands of the Southern Ute
Reservation do not meet part (5)(A)(i)(I) of the definition of critical habitat stated above; we are,
therefore, not designating those lands as critical habitat.
Lands of the Ute Mountain Ute Tribe are not being designated due to the low population density
and isolation from other occupied areas in Colorado, New Mexico, and Utah. The owls on these
lands in southwestern Colorado are not believed to be essential for the survival or recovery of the
species. Thus, these lands do not meet part (5)(A)(i)(I) of the definition of critical habitat stated
above; we are, therefore, not designating those lands as critical habitat.
4.0 Environmental Consequences
This section reviews the expected environmental consequences of designating critical habitat for
the Mexican spotted owl under the proposed action and the environmental consequences of the
No Action Alternative. Regardless of which alternative is chosen, in accordance with section
7(a)(2) of the Act, Federal agencies are required to review actions they authorize, fund, or carry
out to determine the effects of Proposed Actions on federally listed species. If the Federal
agency determines that its action may affect a listed species, it must enter into consultation with
the Fish and Wildlife Service. The consultation results in a biological opinion from the Service
as to whether the Proposed Action is likely to jeopardize the continued existence of the species,
which is prohibited under the Act.
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
15
A similar process would be required if critical habitat is designated. Federal agencies would
have to review their action for the effects on critical habitat, and would enter into section 7
consultation with us on actions they determine may affect critical habitat. That consultation
would result in a biological opinion as to whether the Proposed Action is likely to destroy or
adversely modify designated critical habitat, which is also prohibited under the Act.
Activities that would destroy or adversely modify critical habitat are defined as those actions that
"appreciably diminish the value of critical habitat for both the survival and recovery" of the
species (50 CFR 401.02). Activities that would jeopardize the continued existence of a species
are defined as those actions that "reasonably would be expected, directly or indirectly, to reduce
appreciably the likelihood of both the survival and recovery" of the listed species (50 CFR
402.02). Given the similarity of these definitions, activities that would likely destroy or
adversely modify critical habitat would also likely jeopardize the species when the action area is
occupied by Mexican spotted owl. Therefore, implementation of the Proposed Action would
result in no environmental consequences when compared to the No Action Alternative in
occupied areas.
Potential environmental consequences that may result from implementation of the No Action and
Proposed Actions are discussed below. All impacts are expected to be indirect, as critical habitat
designation does not in itself directly result in any alteration of the environment. Designation of
critical habitat may in some cases provide some benefits to a species by alerting Federal agencies
to situations when section 7 consultation is required. This may be particularly true in cases
where the action would not result in direct mortality, injury or harm to individuals of a listed
species (e.g., an action occurring within a critical habitat area when a species is not present).
Another potential benefit is that critical habitat may help to focus Federal, State, and private
conservation and management efforts. In areas which do not currently contain Mexican spotted
owls, critical habitat designation may have some effect in that it will require Federal agencies to
consult with us pursuant to section 7 of the Act, to insure their actions do not destroy or
adversely modify critical habitat. In the case of the owl, however, we are already consulting with
Federal agencies on activities that may affect the owl within the Recovery Units. Since the
proposed critical habitat units all occur within the Recovery Units, we do not anticipate any
additional impact due to designating potentially occupied habitat within the Recovery Units.
Federal agencies have been required to ensure that their actions do not jeopardize the continued
existence of the Mexican spotted owl since its listing in 1993. The prohibition against adverse
modification of critical habitat is not expected to impose any additional restrictions to those that
currently exist in areas of designated critical habitat.
As required by NEPA, this document is in part intended to disclose the programmatic goals and
objectives of the Act. These objectives include the protection of natural communities and
ecosystems, the minimization of fragmentation and the promotion of the natural patterns and
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
16
connectivity of wildlife habitats, the promotion of native species and the avoidance of the
introduction of non-native species, the protection of rare and ecologically important species and
unique or sensitive environments, the maintenance of naturally occurring ecosystem processes
and genetic and structural diversity, and the restoration of ecosystems, communities and the
recovery of species.
4.1 Effects on the Mexican Spotted Owl
The No Action Alternative would have no significant impacts to Mexican spotted owls in areas
presently occupied by the species because the protections resulting from their listing in 1993 and
the associated requirements of section 7 of the Act are already in place and are duplicative of
protections associated with critical habitat designation.
Implementation of the Proposed Action would provide protection under section 7 of the Act to
areas potentially occupied by the Mexican spotted owl, thus preserving recovery options for the
species. Designation of critical habitat would result in the requirement that any such activities be
reviewed for their effects on critical habitat and that review may result in measures to minimize
adverse effects. Implementation of the no action alternative would forego the opportunity to
provide such benefits.
Benefits to Mexican spotted owl that may accrue from designation of critical habitat would be
the requirement under section 7 of the Act that Federal agencies review their actions to assess
their effects on critical habitat. Federal actions that could possibly adversely affect Mexican
spotted owl habitat are further discussed in section 4.4 below. Designation of critical habitat
would result in the requirement that all Federal actions be reviewed for their effects on critical
habitat and that review may result in measures to minimize adverse effects.
4.2 Effect on Fish, Wildlife and Plants
The No Action alternative would have no significant impacts to fish, wildlife or plants beyond
those protections already in place as a result of listing of Mexican spotted owls in 1993 and
associated requirements of section 7 of the Act.
The objectives of designating critical habitat include the protection of natural communities and
ecosystems, the minimization of fragmentation and the maintenance and restoration of the
natural landscape patterns and connectivity of wildlife habitats, the promotion of native species
and the avoidance of the introduction of non-native species, the protection of rare and
ecologically important species and unique or sensitive environments, the maintenance of
naturally occurring ecosystem processes and genetic and structural diversity, and the restoration
of ecosystems, communities and the recovery of species.
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
17
In areas currently occupied by the Mexican spotted owl, fish, wildlife, and plants may indirectly
benefit as a result of ecosystem protections provided through the conservation of the owl and the
associated requirements of section 7 of the Act. Designation of critical habitat under the
Proposed Action in areas not currently occupied by the owl could provide similar ecological
benefits to fish, wildlife, and plants.
4.3 Recreational Impacts
The No Action alternative would have no impacts upon the continued use of the critical habitat
area for camping, hunting, and fishing beyond any impacts that resulted from the 1993 listing of
the Mexican spotted owl.
Implementation of the Proposed Action would help protect native ecosystems in Arizona,
Colorado, New Mexico, and Utah. The designated critical habitat is mostly composed of Federal
lands (e.g., National Forests, Bureau of Land Management, National Park Service, and National
Recreation Areas) that are managed, in part, for recreation. Neither alternative would impact the
continued recreational use of these areas.
4.4 Agricultural, Including Timber, Fuelwood, and Grazing Impacts
The No Action alternative would have no impacts upon agricultural activities including timber
harvesting and grazing beyond those already resulting from the listing of the 1993 listing of
Mexican spotted owls and the associated requirements of section 7 of the Act.
The implementation of the Proposed Action could potentially affect Federal activities or private
or other non-Federal activities. Under the Act, critical habitat may not be adversely modified by
a Federal agency action; critical habitat does not impose any restrictions on non-Federal persons
unless they are conducting activities funded or otherwise sponsored or permitted by a Federal
agency. The activities that could be affected are those that require a Federal action (permit,
authorization, or funding) and that involve such activities as removing or destroying Mexican
spotted owl habitat (as defined in the primary constituent elements discussion), whether by
mechanical or other means (e.g., timber harvest, right-of-way access, road construction,
development, etc.), including indirect effects that appreciably decrease habitat value or quality.
Federal activities that could be impacted are those that affect protected or restricted habitat by the
Forest Service, Bureau of Indian Affairs, Bureau of Land Management, Department of Defense,
Department of Energy, National Park Service, Federal Highway Administration, or Federal
Emergency Management Agency; vegetative management projects (including timber harvest,
timber salvage, and tree density control activities such as thinning, insect and disease suppression
activities, snag removal, and certain fire/ecosystem projects such as prescribed natural and
management ignited fire); livestock grazing in riparian habitat; land acquisition and disposal; oil
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
18
and gas development; mining and mineral exploration; military maneuvers; road development,
maintenance, and repair; utility construction and repair; construction of campgrounds and other
recreational developments; and access easements.
Actions not likely to destroy or adversely modify critical habitat include “personal use”
commodity production such as fuelwood, latilla and viga, Christmas tree cutting, and most
recreational activities including hiking, camping, fishing, hunting, cross-country skiing, off-road
vehicle use, and various activities associated with nature appreciation. The Service does not
expect any restrictions to those activities as a result of critical habitat designation.
4.5 Socioeconomic Impacts
The No Action alternative would have no impacts to the economic vitality of existing businesses
within the area, business districts, the local economy, tax revenues, public expenditures, or
municipalities beyond those impacts already resulting from the1993 listing of the Mexican
spotted owl and the associated requirements of section 7 of the Act.
The Proposed Action may have some socioeconomic impacts compared to the No Action
alternative if section 7 consultation on Federal actions in areas potentially occupied by the
Mexican spotted owl result in curtailment of those programs listed above (e.g., vegetative
management projects, livestock grazing, land acquisition and disposal; oil and gas development;
mining and mineral exploration, etc.) or other economic activity. Conversely, conservation of
natural ecosystems may provide economic benefits in attracting nature enthusiasts, such as bird
watchers, to the area.
Section 4(b)(2) of the Act requires us to designate critical habitat on the basis of the best
scientific and commercial information available and consider the economic and other relevant
impacts of designating a particular area as critical habitat. We based this designation on the best
available scientific information, including recommendations in the species' recovery plan. We
utilized the economic analysis and our analysis of other relevant impacts, and considered all
comments and information submitted during the public hearing and comment period, to make a
final critical habitat designation.
4.6 Direct and Indirect Effects
Designation of critical habitat in occupied areas is not anticipated to result in direct effects on the
components, structures, and functioning of canyon and forested habitats, or the aesthetic,
historic, economic, social, and health resources of the area, beyond those effects resulting from
the 1993 listing of Mexican spotted owl and associated requirements of section 7 of the Act.
However, at this time, the best available information leads us to conclude that there will be direct
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
19
impacts beyond those already associated with the species listing, in potentially occupied areas
designated as critical habitat. For example, designation of critical habitat in areas potentially
occupied by the owl could provide similar ecological benefits to fish, wildlife, and plants.
Furthermore, a designation of critical habitat will provide some educational benefit by formally
identifying on a range-wide basis those areas essential to the conservation of the species, and
thus, the areas likely to be the focus of our recovery efforts for the Mexican spotted owl.
Indirect effects of the designation that are reasonably foreseeable include focusing conservation
activities by identifying areas that are essential to the conservation of the species, regardless of
whether they are currently occupied by the listed species, thus alerting the public and land
managing agencies to the importance of an area to conservation. Similarly, critical habitat
designation may alert Federal agencies to situations requiring section 7 consultation. Therefore,
the possibility exists that private entities could be impacted if Federal actions are modified by the
designation of critical habitat. While we are unable to reliably estimate those impacts, they are
not expected to be significant.
4.7 Cumulative Impact
Designation of critical habitat for the Mexican spotted owl in presently occupied areas will have
no incremental impact when added to other past, present, and reasonably foreseeable future
actions within the canyon and forested habitats. In potentially occupied areas there may be some
impact on Federal activities. However, we expect this impact to be relatively small because in
addition to the Mexican spotted owl, the subject of the Proposed Action, several listed and
candidate species may occur in the action area. Some of these include the Gila trout, spikedace,
loach minnow, southwestern willow flycatcher, cactus ferruginous pygmy-owl, and the
threatened bald eagle. Federal agencies are required to ensure that any action they authorize,
fund, or carry out is not likely to jeopardize the continued existence of the listed species, or
destroy or adversely modify designated critical habitat in accordance with section 7(a)(2) of the
Act. Activities that adversely modify critical habitat are defined as those actions that
“appreciably diminish the value of critical habitat for both the survival and recovery” of the
species (50 CFR 401.02). Activities that jeopardize a species are defined as those actions that
“reasonably would be expected, directly or indirectly, to reduce appreciably the likelihood of
both the survival and recovery” of the listed species (50 CFR 402.02). According to these
definitions, activities that destroy or adversely modify critical habitat would ordinarily jeopardize
the species. Therefore, designation of critical habitat has very rarely resulted in greater
protection than that afforded under section 7 by the listing of a species. Section 7 consultations
apply only to actions with Federal involvement (i.e., activities authorized, funded, or conducted
by Federal agencies), and do not impact activities strictly under State or private authority.
In practice, the designation of critical habitat for the Mexican spotted owl will likely provide
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
20
little or no additional benefits to the species in presently occupied areas because there are
functioning program activities already alerting Federal agencies and the public of endangered
species concerns. However, there may be some benefits in potentially occupied habitat.
5.0 Council on Environmental Quality Analysis of Significance
Under CEQ 40 CFR Part 1508.27, the determination of “significantly” requires consideration of
both context and intensity.
5.1 Context: Based upon our responses from agencies and the public, although long-term, any
effects will not be national, only regional and mostly local in context; and any that occur are
expected to be small.
5.2 Intensity: Intensity is define by CEQ as referring to the severity of impact. The following
ten points identified by CEQ were considered in evaluating intensity.
1. Both beneficial and adverse impacts may occur as a result of this designation; most are
expected to be beneficial to the environment and any adverse societal impacts are expected to be
small.
2. This designation will not have a discernable impact on human safety. For example, some
commenters questioned whether this designation would cause delays in the Forest Service’s
ability to reduce the risk of catastrophic wildfire in a timely manner. The designation of critical
habitat likely will not require any additional restrictions for section 7 consultations, including
projects designed to reduce the risk of wildfire (e.g., prescribed burns, mechanical thinning, etc.).
3. Although several areas designated as critical habitat are in proximity to historic and cultural
sites, parklands, farmland, wetlands, scenic rivers and ecologically critical areas, no major
adverse impacts will occur to these areas; in fact, the ecologically critical areas are expected to
only benefit from this designation.
4. There is a perception by some segments of the public that critical habitat designation will
severely limit property rights; however, critical habitat designation has no effect on private
actions on private land that do not involve Federal approval or action. Therefore, we conclude
that this misperception will be clarified by the Final Rule and will result in this designation not
being highly controversial.
5. The Service has designated critical habitat for other species in the recent past and we are
familiar with the associated affects. Therefore, we do not anticipate any effects to the human
environment and we are highly certain this action does not involve any unique or unknown risks.
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
21
6. This designation of critical habitat is not expected to set any precedents for future actions with
significant effects or represent a decision in principle about a future consideration because
critical habitat has been designated before for other species, as required by law, often in close
proximity to or within the same lands involved in this designation.
7. This designation of critical habitat will be additive (cumulative) to critical habitat that has
been, and will be, designated for other species. However, it is the Service’s conclusion that the
beneficial and adverse impacts of any and all critical habitat designations are small, and therefore
insignificant, due to the existing impacts, both beneficial and adverse, already resulting from the
listing of the species involved.
8. This designation will have no adverse effects to National Register of Historic Places or other
cultural sites and it could possiblly benefit historic sites near forested areas due to focusing
conservation efforts on reducing the risk of catastrophic wildfire.
9. All impacts from this designation of critical habitat are certain to be totally beneficial to
endangered and threatened species, particularly the Mexican spotted owl.
10. This designation of critical habitat will not violate any Federal, state, or local laws or
requirements imposed for the protection of the environment.
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
22
REFERENCES CITED
Fletcher, K.W. 1990. Habitats used, abundance, and distribution of the Mexican Spotted Owl.
Unpub. Report U.S. Department of Agriculture, Forest Service, Region 3, Albuquerque,
New Mexico. 56 pp.
Fletcher, K.W, and Hollis, H.E. 1994. Habitats used, abundance, and distribution of the
Mexican Spotted Owl. Unpub. Report U.S. Department of Agriculture, Forest Service,
Region 3, Albuquerque, New Mexico. 86 pp.
Forsman, E.D. 1981. Molt of the spotted owl. Auk 98:735-742.
Ganey, J.L. 1988. Distribution and habitat ecology of Mexican spotted owls in Arizona. MS
Thesis. Northern Arizona University, Flagstaff, Arizona.
Ganey, J.L., and R.P. Balda. 1989a. Distribution and habitat use of Mexican spotted owls in
Arizona. Condor 91:355-361.
-----. 1994. Habitat selection by Mexican spotted owls in northern Arizona. Auk 111(1):162-
169.
Moen, C.A., A.B. Franklin, and R.J. Gutierrez. 1991. Age determination of subadult northern
spotted owls in northwestern California. Wildl. Soc. Bull. 19:489-493.
Seamans, M.E. and R.J. Gutiérrez. 1995. Breeding habitat of the Mexican spotted owl in the
Tularosa Mountains, New Mexico. Condor 97:944-952.
Skaggs, R.W., and R.J. Raitt. 1988. A spotted owl inventory of the Lincoln National Forest,
Sacramento Division, 1988. Share with Wildlife Program Contract No. 5-516.6-76-17.
New Mexico Department of Game and Fish, Santa Fe. 12 pp.
USDI Fish and Wildlife Service. 1991. Mexican spotted owl (Strix occidentalis lucida) Status
Review. Endangered species report 20. Albuquerque, New Mexico.
USDI Fish and Wildlife Service. 1993. Endangered and threatened wildlife and plants; final
rule to list the Mexican spotted owl as a threatened species. Federal Register 58:14248-
14271.
USDI Fish and Wildlife Service. 1995. Recovery plan for the Mexican spotted owl (Strix
occidentalis lucida). Albuquerque, New Mexico. 85pp.
Environmental Assessment - Mexican Spotted Owl Critical Habitat Designation
January, 2001
23
USDI Fish and Wildlife Service. 1998. Endangered and Threatened Wildlife and Plants;
revocation of critical habitat for the Mexican spotted owl, loach minnow, and spikedace.
Federal Register 63:14378-14379.
USDI Fish and Wildlife Service. 2000. Endangered and Threatened Wildlife and Plants;
proposed designation of critical habitat for the Mexican spotted owl. Federal Register
65:45336-45353.
USDI Fish and Wildlife Service. 2000. Endangered and Threatened Wildlife and Plants;.
reopening of comment period on proposed critical habitat for the Mexican spotted owl;
availability of draft economic analysis and draft environmental assessment. Federal
Register 65:63047.
Ward, J.P. Jr., and W.M. Block. 1995. Mexican spotted owl prey ecology. In Mexican Spotted
Owl Recovery Plan. U.S. Department of the Interior, Fish and Wildlife Service,
Albuquerque, New Mexico.
Young, K.E., R. Valdez, P.J. Zwank, and W.R. Gould. 1998. Density and roost site
characteristics of spotted owls in Sierra Madre Occidental, Chihuahua, Mexico. Condor
100:732-736.